Three foam blocks in graduated sizes, 47-in, 28-in and 20-in, that work alone or nest into one arc. The large piece carries the shape: rocked on its curve it becomes a rocker, arched the other way it makes a crawl tunnel, and laid flat it serves as a low table. High-resilience foam under suede covers springs back rather than staying dented after a long session. Covers unzip and go through the washing machine. Note that the blocks ship compressed and take about 48 hours to reach full shape. Built to ASTM and CPSIA standards for children aged 3 and up.