The picture above and the one to follow celebrate a breakthrough. In creating a geomagic square, the choice of admissible target shapes is usually tightly constrained. Careful scrutiny will show thatthe target here is essentially a simple chain of 4 pieces. But two of the pieces, both yellow, always occur at the ends of the chain, which means they can take on almost any shape, with impunity. Here they have been made to meet, and so envelope the chain itself, the shape of their combined outline then being entirely up to the constructor.