It took 3 months to build the first version in 2008, and an additional 2 weeks for an updated version in 2009. All of it is completely hand-made out of craft foam, foamboard, vinyl, and polystyrene plastic sheeting. The most difficult part was designing for comfort and mobility. I could be in it for hours and hours and not have to worry about keeling over from exhaustion. It’s really very lightweight.