Mystery Knick-Knack

Matthew Gregori has a bit of a mystery on his hands. He's received a gift produced on a 3D printer, but doesn't know what it is. Here's the description:

I received a gift from a client that was produced on his 3D printer. It consists of a square base with 2 perpendicular slots with a rail fitted into each slot. The 2 rails are attached to a handle such that when the handle is turned, the 2 rails slide back and forth past each other. The knob at one end of the handle traces out the shape of an elipse.

Can anyone shed light on this?

Via LinkedIn