The key was a certain fun tactility as you dragged the body block off the palette and onto the spine.
How it snapped in place and slid around clicking and snapping in small increments along each spine segment.
You could then attach other blocks to this main block and they would move with it and the parent spine segment.
You could also reduce the number of spine segments or add them by pulling end handles (like in Spore)
A decent robot could be built with 2 or 3 spine segments, but more complex behaviors could be made with
longer spines.
