name of thingy

i used to have a plastic block about 20x20 big and 2-3 cm thick. and there were hundreds of holes with iron pins in it. you could move all the pins to one side so when you would push your hand onto the pins, the shape of your hand would be formed by the pins on the other side of the plastic plate...
damn hard to explain...

does anyone know what that thing is called?? :P