plastic. and the way it does that is it pulls plastic in from a spool, and squirts it through a little nozzle and it draws and then it lifts up a little bit and draws another picture in plastic on top of that picture, and layer by layer, it builds up the model. bree and a group of gear head friends got together and cobbled together a 3-d printer a couple of years ago, and now his brooklyn based company is at the hub o testify 3-d maker revolution. when we got our prototype to work, we quit our jobs. our goal was to change the game and bring 3-d printing to people, so they could put them on their desktop and actually innovate personally. and just like the replicator in star trek, maker bot s