If you watch a key duplicator working, you understand the 2D version of this concept. Now what if both keys (the copied key and the duplicate key) rotated during the grinding process. You'd have a duplicator. This is probably well known in manufacturing circles, so what is perhaps novel is the extreme low cost and 3D printability of the design.
So let's picture a typical use scenario. You are a parent decorating a cake for your child's birthday. The child has a favorite toy that you would like to copy in Chocolate for a cake topper. You don't need a scanner, 3D software, a chocolate 3D printer, and the skills to operate all that stuff, you just need a DupliGator! A little careful operation of the device and a copy or mirror image copy of the object in chocolate is on the cake.
The "Gator" in the "DupliGator" name is a play on words to encode my sister's alma mater, the University of Florida Gators as a nod to her success.