Anthony Atala of the Wake Forest Institute of Regenerative Medicine “printed” a kidney (actually, “a kidney-shaped mold”) on Thursday at a TED Conference in Long Beach, California.

Scanners are used to take a 3D image of a kidney that needs to be replaced, then a tissue sample about half the size of a postage stamp is used to seed the process, he explained . The organ printer then works layer-by-layer to create a replacement kidney replicating the patient’s tissue.