Super Mario Bros. kitchen hooks for IKEA STUGVIK suction cups.
The suction cups will completely disappear behind the tubes, so it basically looks like the mario scene was just sticked to the wall.
There are four holes in the bottom of each scene for the hooks. They can easily be fixed with hot glue from the inside of the scene (the blocks are hollow from behind).
Printed with the back of the scene down on the plate.