Why a plank? Well, for one, it fits the pirate theme. When plugged into the Bus Pirate, the expansions also look a bit like a plank hanging out over the side of a pirate ship. As an example ...

Let's Jump (Walk the Plank) Song Find out what happens to naughty pirates with Gem, Cook, Line and Captain Captain! Can your little one sing, dance and jump on the pirate plank?