Click a pin to select or unselect; space to clear all selected pins. Keys 1 to 5 to set pin height. M - Toggle pins to follow mouse F - Flip order (to fix problem of pins behind) R - Resets all pins to height 1.
An attempt to make pin art on Scratch I received a Pin Art board where you create 3D art by pushing pins in a board. I wondered if it would be possible to simulate this in Scratch.