The Schrödwich is made by placing the CAT-IN* box between two slices of bread. The box is a wedge shape; the wide end is pre-loaded with a prodigious selection of sandwich filling ingredients, and the pointed end, between the two slices, has a nozzle where the fillings are extruded.
As the user takes a bite, the machine inserts a randomly chosen ingredient between the bread between the user's teeth.
*Concealed AuTomatic INserter-- pocmloc, Jun 19 2011 No poison vials, (also known as vegemite) I hope?-- RayfordSteele, Jun 20 2011 random, halfbakery