This accessory dwelling unit (ADU) has become a top-selling plan. That’s remarkable for such a small design. Why is it so popular?. Lucas Roetcisoender of JWR Design says the plan provides “a flexible living experience that gives opportunities for additional dwelling units, temporary housing while they save to build their dream home, or an ‘easy-living’ space that is easy to clean with the ability to store boats and RVs. The plan fits many lifestyles and seasons of life, all while resembling the shape of a barn that will positively influence the overall property aesthetic.”