92° Build me a tree.
Specifications? It has to be 50′ to 60′ tall, but no more than three feet in circumference at ground level. It has to provide oxygen and absorb carbon dioxide from the air. It has to run on solar power, but it can use water and natural elements found in the soil and air. It must provide shade in the Summer, but let the sunshine through in the Winter. It has to last over 60 years, but when it stops working it must still be useful for building and/or fuel.
Cost? Oh, I’m not paying you for this tree. It must be free.
Where are you going?