Hacker help: How to stack 2 Lillangen together?

Photo: IKEA.com

Materials: LILLÅNGEN wall cabinet

Description: I have a small entryway, I was thinking about placing 2 LILLÅNGEN wall cabinets one on top of the other (possibly placing the top one upside down as a sort of desk) SOMEHOW, adding some feet/leg frames.

The point is how to stick them together… as I am totally unable to drill things to the walls. Any ideas?

~ chiara, Milan, Italy.