Prosparity Systems

Our innovation enables the capacity to buffer against economic shocks, generate economic opportunities, and develop jobs and related workforces. 

In sub-Saharan Africa, as other applications have noted, damaged and non-existent rural roads limit physical access to markets (pg. 8), increase logistics costs (pg. 51), and render conventional transport and cultivation machinery ineffective or uneconomical - impacting agribusinesses and perpetuating subsistence farming, drudgery, poverty, and inequality for farmers, women and youth. 

“It is now time to banish the hand hoe to museums, instead of it being the symbol of women farmers in Africa.” – Former Chair, African Union Commission  

“With a hand hoe for a tool, a poor person can neither attain food security nor break away from poverty.” – Former President, Tanzania

These road constraints are a key contributor to three overarching issues in sub-Saharan Africa: 

1. The lack of essential mechanical power in vast rural farming regions; 
2. The resulting vulnerability and lack of opportunity; 
3. The reality that 1 and 2 combined are driving one the largest crises of youth unemployment and out-migration in the world.

Approximately 276 million Africans are between the ages 10 and 24 years. By 2050 this age group is projected to reach 561 million (link). 60% of Africa’s unemployed are young adults (pg. 21).And roughly 50% of today’s rural youth are considering moving away (pg. 15), fueling Africa’s record urbanization.  

“The UN should declare the hand hoe a weapon of mass urbanization” – CEO, Malawi National Smallholder Farmer’s Association (3rd paragraph from bottom)

Amazingly, this is happening in a region with around 40 million small-scale farms (pg. 72) and 40% of the world’s unused agricultural land (pg. 14). Unfortunately, SSA has the lowest farm power of any developing region (pgs. 3-4) a decades-long issue linked to road constraints.

What does this mean? It means that human power – the largest source of farm power for one of the greatest concentrations of untapped food production on Earth – is draining out of the system, as a mass exodus of youth attempt to escape drudgery, hunger and lack of economic opportunity. Experts alarmed at the scale of the challenge describe it as a ‘ticking bomb’ for potential unrest, instability and conflict (ex 1, ex 2).

“A hungry man is an angry man.” – Bob Marley 

The Service Rover Vehicle (SRV) is a low-cost, locally producible, all-terrain truck/tractor, engineered to provide cost-effective transport and mechanization services in farm regions where roads are inadequate and terrain is rugged and uneven. As a truck, it can haul 1.2 tons across a 30-degree slope and up a 70 percent grade. At farms, it converts to a multi-function light tractor, with front and rear 3-point hitches and up to four types of productive power: rotational, hydraulic, electric and compressed air (image 1) (image 2).  

The SRV’s enabling technology is an interlinked torsion bar suspension system that works to level and stabilize the chassis on rugged roads and terrain at surprising speed with minimal impact on components and cargo. The system also retains traction/downforce at extreme articulations and preserves forward momentum, lowering energy and fuel requirement.  

The underlying all-terrain technology was developed, tested and proven across 4 prior prototype vehicle programs under extreme terrain and conditions for years (see section "more about your solution"). We worked closely with our partner who developed the technology, to simplify and adapt it for African context and develop the truck/tractor platform around it. This was a considerable, years-long engineering effort, informed by a large library of research literature and globally respected experts at the forefront of smallholder mechanization.

Agribusinesses who combine and resell crop from around 4 million smallholder producers are scaling in many areas, and some provide tech-enabled services. These businesses have a critical need to overcome upstream road constraints; they access just a fraction of farms and struggle with logistics, yield quality, post-harvest losses and transport costs. Many need to integrate inefficient services performed by informal actors with inadequate technologies. These unmet needs generate compounding costs and yield shortfalls along the value chain for these businesses and their customers.

There are many examples of this. One is MIT-selected team, Cold Hubs. Despite the remarkable achievement of scaling 60 hubs across 28 states and operating a fleet of downstream trucks, they’re still losing up to 30% of perishable crop upstream. 

Our solution hauls 2x load at 2x speed for half the cost while doubling farms reached and enabling additional transport and mechanization revenues. This is why Cold Hubs and others are interested in building and servicing their own fleets of our vehicles. 

Millions of smallholder producers live in communities isolated from roads (pg. 51). These farmers transact with digital technology, but they cultivate with biblical technology, unable to climb significantly out of poverty - while all around them researchers the tractors rusting into the ground, the feeder roads disintegrating, and the changing climate working against them. Furthermore, these farmers pay for first-miles transport from fields to roadside aggregation. In other words, the poorest people pay for the most-expensive transport (pg. 28) and sell to typically the lowest paying buyers (pg. 6) – simply because the road, or all-season road, isn’t there. 

For agribusinesses and farmers, our solution improves profits and enables essential services that reduce costs and losses while increasing operations, land under cultivation, and quantity of delivered quality yields. 

For rural youth and women without land rights, the businesses deploying our vehicles will be able to offer vocational opportunities: vehicle assembly, maintenance, service provision, entrepreneurial opportunities (details available). Across Africa, as a growing chorus of leaders trumpet the need to “make farming ‘sexy’ for Africa’s youth,” (ex. 1, ex. 2, ex.3), our innovation presents a compelling, sustainable path. 

For donors and recipient country governments, our innovation increases agricultural and economic productivity without having to build and rehabilitate roads. Road agencies are notoriously underfunded; they cannot extend feeder roads and address mounting backlogs of road deterioration accelerated by climate change (pg. 7). Our innovation - a solution that doesn’t need roads and is built and maintained by local businesses - provides a lifeline to agencies struggling to increase rural productivity and economic competitiveness through improved, reliable infrastructure (pg. 15).   

Engineering for small-scale mechanization in Africa is deceptively difficult. Many shelved prototypes from knowledgeable teams following best practices (including proximity) failed to increase livelihoods enough for the innovation to matter. A common thread was the absence of engaged world-class engineers. 

This is why Prosparity was founded on the principle of leveraging informed, world-class engineering to confront sub-Saharan challenges. To increase proximity to problems and communities, we read the research for three years, engaged experts in smallholder mechanization, engaged businesses across Africa, and used that knowledge to inform engineering.  

The literature review netted three advisors: Rabe Yahaya, (IRRI, CIMMYT, FACASI, AGCO, CLAAS) is driven by his passion to sustainably transform smallholder livelihoods. Scott Justice has worked in the field with smallholders for decades: Bangladesh achievement of 80% smallholder mechanization, initiatives in Ghana, etc. And Richard Tinsley’s advocacy for smallholders and a hands-on career in 24 countries speaks for itself.

Co-Founder, Eric Lane, is driven by vehicle innovation that improves lives and economies. Eric conducted strategy and research for the consumer version of the VLC project (Very Light Car). The VLC won the $10m X-prize, was praised by a congressional panel on climate change, and is now in the Henry Ford Museum. Eric is in regular contact with African agribusinesses, constantly refining product and project per their input.  

Late Co-Founder Engineer, Ron Mathis, wanted to create transformative machinery for those in need. Ron developed concepts for our vehicle suspension and architecture. He led engineering for the VLC project, for vehicles that won 24 hours of Le Mans & Daytona etc., and for the XCOR Lynx suborbital spacecraft. We had a devastating setback when we lost Ron in a tragic accident.

Eric rebuilt the project with partner Dimitris Korres of Korres Engineering, a gifted compassionate multi-discipline engineer: covid ventilators for Greece, a vehicle for disabled, hi-profile civil engineering, technologies that move ancient cities and buildings for the Minister of Culture, etc. Prior to our project, Dimitris developed the enabling technology and 4 prototype vehicles, including the first all-terrain supercar. Dimitris has the team, facilities, affiliates and testing grounds to execute our innovation.

Before partnering with Prosparity Systems, Korres Engineering developed tested and proved the enabling technology across 4 prior prototype vehicle programs listed below.  

Prosparity was engaged in SRV development, lost their co-founder in a tragic accident, continued that work with a university team, attracted Korres Engineering, partnered and restarted SRV development around the Korres technology.

The Korres technology was re-designed and adapted to African context, during which 3 iterations of the truck/tractor platform were developed around the technology. Two SRV demo vehicles were under construction until funding constraints. Without funding, a full-scale prototype of the new SRV suspension was constructed and retrofitted into 1 of 2 identical OEM production vehicles and testing is in progress.  

Technology development prior to Prosparity Systems SRV development

Korres Engineering: Four versions of the enabling technology developed. Each version validated, tested and proven in a prototype vehicle designed from the ground up

• P1 – Testing platform and technology demonstrator (video)
• P2 – Advanced technology demonstrator (video)
• P3 – Proof of concept recreational vehicle (video)
• P4 – Production prototype all-terrain supercar (video1) (video2)

Development of the Prosparity Systems SRV  

SRV1 Development

Development with late co-founder:

• Research and engagement to inform engineering
• Design Brief, technical investigation, concept development 
• Develop initial technology and vehicle architecture
• Initial general assembly/integration
• Loss of engineering co-founder in fatal accident

Development with Colorado School of Mines Engineering, 9-engineer team

• Repeat development process, using late co-founder work to date
• Discover and secure engagement of partner Korres Engineering
• Korres Engineering accelerated coaching of 9-engineer team
• Complete and integrate late co-founder suspension and architecture concepts
• Exhibit student work (video)

Development with Korres Engineering

• Repeat development process, using Korres technology to date
• Adapt Korres suspension technology to African context
• Develop, refine initial core systems, including hybrid electric driveline
• Pivot to standard driveline, develop transmission and driveline
• Design and validate V1 of the SRV suspension technology
• Complete general assembly of SRV 1 multifunctional Truck
• SRV1 - First iteration complete

SRV 2 Development

• Ground-up redesign of SRV: design for manufacturing, minimize parts/complexity
• Develop and validate V2 chassis for tractor work – ground up redesign
• Develop and validate V2 suspension – ground up redesign 
• Develop light tractor PTO and hydraulic systems
• Validate and finalize transmission and driveline systems
• Finish driver ergonomics, functionality, gender-agnostic operation
• Systems integration, including generator and compressed air power
• Complete general assembly of SRV 2 multifunctional truck/tractor platform
• SRV2 - Second iteration complete

SRV 3 Development

• Ground-up redesign of V3 chassis: easier, low-cost manuf., increased capability
• Finish front, rear and side PTO system
• Finish linkage systems for transmission and steering
• SRV3 – MVP development complete, ready for construction

Begin construction of two (2) demonstration SRV

• Construction stopped due to funding constraint: global macro-economic events

Pivot to construction/testing of prototype SRV suspension

• Build full-scale SRV 3 prototype suspension 
• Retrofit prototype into 1 of 2 identical purchased Fiat Panda 4x4
• Conduct initial comparative analysis 
• Initial analysis indicates capability far exceeding OEM technology 

Over time we’ve learned that developing an all-terrain hardware solution to overcome intractable road problems in Africa isn’t on the minds of the development sector, or in the bullet point objectives of grant challenges or grand challenges. That said, Africa’s Road issues are both everyone’s problem, and no one’s problem; everyone is impacted but no single entity is responsible or has the capacity to address it. 

When everyone is resigned to a problem no one believes is solvable, there is no dialog. Without dialog, the programs to seek a solution like ours aren’t created, and we end up outside the scope: we’re early, we’re late, or the target program isn’t structured for what we’re doing.  

With this accelerator, we hope to find groups seeking dialog on solutions like ours. More importantly, groups with the capacity to open, influence and accelerate dialog about supporting a solution like ours in networks who stand to benefit the most.  

We would benefit from technical go-to-market assistance, navigating the intricacies of implementing a solution like our in a developing market, as well as legal considerations for rights, licensing, royalties and joint ventures. We are open to any coaching, insights, strategies, networking and support, and open to being influenced. We welcome this opportunity.  

The prevailing logic in donor and development sectors is roads are required to spur economic productivity; and economic productivity is required to sustain roads. This logic breaks down in Africa’s vast rural farming systems where the top agenda is agricultural productivity, but population and farm density are too low to sustain a road, even if it were built.

However, the rural roadbuilding agenda continues, despite lack of economic activity. Roadbuilding issues are beyond scope of this application, but in short, two outcomes of this approach are 1) roads that are poorly maintained, creating billions in shortfalls (pg. 84), and roads being abandoned until donors fund reconstruction (pg. 42) at billions more than maintenance (pg. 41). This is just a glimpse into why approaching the problem with roadbuilding is not working, and roads remain a top constraint.

Our solution and approach strike at the center of this issue by enabling agricultural and economic productivity without having to build or rehabilitate roads. It begs the question: instead of building roads because machines require them, can machines be built that don’t require roads?

On that topic, a common approach for building agricultural machinery is centralized factory production. In Africa, that often means exporting jobs and money and importing machines. This approach works against development agendas (details available). 

Machine import is followed by aftermarket support, but only if destinations have adequate economic activity to justify it. Much of rural Africa does not, and the outcome is strikingly similar to roads: Nigeria’s NIRSAL program is slated to rehabilitate 10,000 tractors per year for 10 years. This indicates the magnitude of a problem caused by an approach that is not working in rural Africa.   

In our approach, the SRV is engineered to bypass the roads issue, and designed to be built near rural regions inside modified shipping containers from simple kits using low tech tools and trainable methods. Containers and kits can be assembled in Africa and distributed to businesses near farming regions who want to build and service their own fleets. The resulting scalable network enables technology transfer, brings light manufacturing to Africa, and spatially distributes essential tools, machines, parts, jobs and opportunities where they’re needed most. This approach targets a series of highly recommended development strategies.

Combined, our vehicle solution set and strategy are a novel approach, intentionally designed to be in high alignment with development strategies. This slide with clickable links illustrates. 

Prosparity Systems has developed a low-cost, all-terrain truck/tractor that doesn’t need roads to provide essential agricultural services to rural sub-Saharan smallholder farming communities. 

In sub-Saharan Africa, most of the rural population are underserved by roads (pg. 100). Consequently, physical access is nearly as great a constraint as rainfall (pg. 8), and the agronomic potential of a farm plummets as hours to market increase (pg. 13). Unfortunately, addressing this could require doubling the roads (pg. 238) in a region where up to 30% of existing roads need to be rebuilt (pg. 36). If roads are key to productivity, and GDP growth from agriculture reduces poverty 4x more than anything else (pg. 315), then overcoming road constraints is an impact opportunity.  

For brevity, we've limited theory of change to the vehicle in truck configuration. There are theories of change for in-country, local production that exceed application scope but also impact poverty, opportunity and economic productivity.

In truck configuration, our innovation enables the following inputs and results:

1. Our solution overcomes road constraints, resulting in 1) more physical links between farms and buyers, 2) extension of existing roads.
2. Our vehicle carries at least 2x load vs. solutions in use (data available), resulting in greater load consolidation, a crucial need for farmers.
3. Our vehicle can move at 2x speed vs. solutions in use, without damaging vehicle or crop, resulting in 1) more loads per day of 2) less damaged, more valuable crop.

The above results can be linked to these potential outcomes

1. The result of more physical market links have been correlated to outcomes of 1) more inclusion into markets (pgs. 1-2), 2) increased livelihoods (pgs. 1-2), 3) more crop to market (pg. 3) and 4) likely more land under cultivation (pg. 3)
2. The result of greater load consolidation enables the outcomes of 1) lowering costs for farmers (pg. 51), and agribusinesses, and 2) helping to improve livelihoods, productivity and business margins.
3. The result of more loads per day with less damage to crop and vehicle enables outcomes of 1) reducing post-harvest losses, 2) lowering overhead, and 3) improving margins and productivity for farmers and downstream businesses. Data from customer interviews support this.

 “We need this yesterday, and it cannot come soon enough” is a common reaction, and customer interest in managing their own fleets of our vehicles to integrate operations is strong. That said, there’s an untested assumption from our customers they’ll efficiently deploy and support our solution and convince donors and investors to fund.

Our solution has many features/liabilities of disruption: the implications and impacts are many, with myriad links and new assumptions that have never been tested or quantified before. This is often the nature of disruption, and why supporting disruption is essential.   

In vehicle development, key indicators to track progress against an impact goal are only achieved when a large sub-set of indicators (beyond application scope) are met. Failure to achieve any key indicator below triggers a failure point in the capacity our innovation to achieve the impact goal and contribute to achieving the goal’s related SDG indicators. 

We’ve shared two example impact goals and a sampling of the key indicators for each. 

Impact goal 1

Poverty reduction and hunger reduction by cost-effectively creating, increasing and improving physical links between farmers and buyers. These links help contribute to achieving SDG 1 indicators 1.1, 1.4, and 1.5, and SDG 2 indicators 2.4, 2.5, 2.6.

Key indicators – each indicator has a long list of metrics (details available). Achieving/meeting these indicators results in an innovation capable of achieving Impact Goal1 and thus contributing to achievement of related SDG 1 and SDG2 indicators.

1. Enabling technology (all terrain suspension) adapted to African context. 
2. Truck vehicle developed (architecture, all systems, integrated with enabling technology)
3. Truck engineered to haul 1.2 tons in extreme terrain
4. Truck & suspension system capable of 2X speed on rugged road and variable terrain vs. existing solutions, without transmitting force impacts into chassis, components and cargo.

Impact goal 2:

Gender Equality, through development of an agricultural machine engineered for gender-agnostic, low-strength operation, and trainable maintenance and repair.  

Key indicators – each indicator has a long list of metrics (details available). Achieving/meeting these indicators results in an innovation capable achieving Impact Goal2 and thus contributing to achievement SDG2 indicator 5B.

1. Designed: Steering and implement operation for persons of low strength 
2. Designed: Operator controls for 6 vehicle functions simple to understand and operate and easily trainable.
3. Designed: Vehicle technologies and systems that are, 1) common technologies, known and understood by regional mechanics who can train women and youth, and 2) engineered such that components and systems are easy enough to access that women and youth can be trained to perform most vehicle maintenance and repair tasks.

Our enabling technology is a simple, interlinked torsion bar suspension system that connects the wheels together, replacing conventional springs, dampeners and related structures. Conventional suspensions transmit the impact forces of obstacles like a speed bump into the chassis. Our system passively harnesses and transmits that force energy through the torsion bar system to the other wheels, pushing them into positions that level and stabilize the chassis on rugged roads and terrain at surprising speed. By harnessing impact forces and putting them to work, our technology dissipates the impacts that damage vehicle components and fragile crop while retaining and preserving critical forward momentum – reducing energy and fuel requirement. 

The system also evenly distributes the vehicle weight downforce/traction across every wheel during extreme articulation, far exceeding the traction and articulation capability of existing technologies (sample illustration).   

General behavior of the enabling technology is observable in these videos from prior prototypes used to develop and prove the technology

1. P1 technology demonstrator: (video)  
2. P2 technology demonstrator: (video)
3. P3 proof of concept all-terrain supercar: (video)
4. P4 production prototype all-terrain supercar: (video)

This image (link) is a brief summary of our strategy to adapt and apply the enabling technology to the road constraints impacting rural economies and populations -- and our executed design brief, to deliver a truck/tractor platform with appropriate power and function, aligned to regional contexts.    

Full-time staff: 1

Part-time staff: 1

Other workers: 3

8 years total 

5 years developing SRV1, iteration one, due to death of co-founder and re-starting development twice. 

2 years developing SRV2, iteration two, a complete ground-up redesign, to improve and expand vehicle capability, and to better align design to manufacturability and a number of SDGs, development targets, and recommended strategies to achieve development targets.  

1 year developing SRV3, iteration three, a ground-up redesign of the chassis and refinement and finishing of a number of final items. 

A core operating tenet of our project is that valuable and essential ideas, work, feedback, contribution, insights etc. can come from anyone, regardless of the dimension or extent of their diversity. 

Though we are a startup without significant organizational structure or hierarchy, we have enthusiastically engaged on equal terms, with equal interest, with equal opportunity, as diverse a range of people as possible. In fact, the process of actively seeking out and pursuing diversity has delivered and continues to deliver competitive advantages to our project and all engaged stakeholders.    

Without inclusion and diversity, we would not have been to develop an innovation in alignment with the problems it seeks to address. Nor would we have understood those problems, or begin to understand the myriad of nuances across cultural contexts impacting our innovation and vice versa. As our project progresses and evolves, we will strive to progress and evolve this core operating tenet.

Business Model summary: Our core business and revenue activity will center around providing the capabilities for our customers to build and service their own fleets of vehicles to provide essential services to the farms they engage. Our current model for vehicle manufacturing, distribution and revenue is based on the assembly of simple vehicle kits and the modification of standard shipping containers to build those vehicle kits. Details available. 

Implementation Summary: Global partner-vendors will manufacture and ship standard shipping containers and parts in bulk to an African subsidiary for bundling. The subsidiary will separate and organize the bulk parts into bundles 1) bundles for assembling vehicle kits and 2) bundles for modifying containers. Bundles will ship to African partners who are already assembling other machines from kits. Those partners will assemble the kits for building vehicles, and modify the containers so vehicles can be built inside of them. Once kits and containers are ready, they will be distributed to our customers. Our customers will use the containers and kits to build, service and scale their own fleets and provide essential services. We will provide ongoing supply chain services, scale up the implementation, and replicate the model in other regions. 

The goal of our business model is to create a repeatable and scalable process that enables technology transfer, brings light manufacturing to Africa, and spatially distributes essential tools, machines, parts, jobs and opportunities into rural regions where they’re needed most. Per our research into donor and country development targets and SDGs and related strategies from advising entities, this model and implementation have the greatest number of alignments.    

 At this early stage in our startup, this very general summary is a work in progress without significant detail. We will progressively elaborate, investigate and test feasibility, and validate extensively as we work to fund our top priority: build and pilot of a demonstration SRV. 

Our key focus to date has been engineering a vehicle platform that’s as easy and as cost-effective as possible to manufacture, ship, assemble, distribute and build, using the simplest, lowest investment methods: from manufacturing components, to building at a customer destination, to servicing over time.  

We expect to make revenue from vehicle and container kits, supply chain services, licensing, rights, royalties, joint ventures and related services (details available). Calculations indicate that revenue from 1 portion of 1 of 7 possible vehicle revenue streams (not including reaching more farms) is sufficient to support product margins and royalties by itself. This indicates we can expand revenue strategy beyond margins and royalties to the revenues above. 

When considering a disruptive innovation, especially hardware, business plans and forecasts are often untested and hard to accurately quantify and validate. As a result, disruption often exists outside the scope and objectives of many investors and programs. We hope application judges keep this in mind when considering our project and innovation.  

Background: Development of enabling technology and vehicles prior to Prosparity was funded by $3m from investors who can’t participate in Prosparity. We bootstrapped over $250k for work to date (see ‘stage of development’) and have come as far as we can on our own. Opportunities with Bayer Global, AgDevCo, customers and grant programs we’ve engaged require a full vehicle system built and piloted, with requisite data, which costs up to $500k. Bayer and AgDevCo don’t fund hardware. Our customers can’t fund without pilot and data. And the grant sector which usually funds expanded pilots and scale-up, mostly isn’t structured for building a vehicle. Several projects said SBIR was unproductive and very time consuming.  

Having learned this, we pivoted to this summary plan: 

1. Construct full-scale prototype of enabling technology, now installed/testing in an OEM vehicle. 
2. Apply to accelerators and expand networking via existing leads and receptive accelerators
3. Organize interested customers to sign a consortium document (representing up to 300k farmers and 2m MT production), declaring need for our innovation, interest in deploying, and need for Africa demo vehicle.  
4. Conduct coordinated document release to all customer donors and investors, including delivery by our Bayer contact to the team at Gates Foundation Bayer works with.  

Summary plans when a demo vehicle is funded:

1. With customers: build LOIs, pre-orders, deposits that trigger as milestones for build & pilot are met – use those to raise grants/investments. 
2. Use raised capital to build & pilot a production-intent fleet and demonstrate the container & kit vehicle production product. During this, repeat same milestone-based system to raise follow-on capital and establish supply chain partners. 
3. During # 2, prove business model, traction, revenues, and scalability required for conventional capital and later donor/impact sector engagement.  

These plans will progressively elaborate and refine. Given our alignment with development strategies, large donor/impact capital is possible, but we’re not relying solely on those sources.

Financial sustainability for our business and our customers is derived from the increased net economic output enabled our innovation vs. existing solutions. Evidence of this already exists in our vehicle specifications and transport data (with existing solutions) provided by customers. We estimated 2x load at 2x speed for half cost vs. solutions in use. Results of a conservative comparative analysis (transport of 2 crop types) shows 4x net value delivered at 1/4th the operating cost. That alone supports pricing vehicle kits at 2x CoG and $3k yearly royalty per vehicle.  

Revenue above does not include: 1) revenue from ability to reach at least 2x more farms, 2) other crop transport, 3) other transport services, 4) up to 4 light-tractor revenue streams. Add to these the economic efficiencies gained using a single-asset truck/tractor, in-house maintenance, and other efficiencies engineered into the platform. As we elaborate business and revenue models, we believe now, as we did when starting the project, that the economic output of our innovation is the key to financial sustainability.