Squeeze-Away Block Illusion

This is a truly baffling stage illusion! You hand out three wooden blocks to be inspected...two red, one yellow. They are then placed into the wooden shelf where they are openly displayed. The yellow block is in the middle. After weaving a spell, you begin to push the two red blocks together, impossibly squeezing away the yellow block entirely!

THIS LOOKS INSANE!

You then remove the two red blocks, and hand them out...the top shelf has no doors, and can be seen all the way through. 

No shells, no duplicate blocks...just clever craftsmanship and ingenuity. These are no longer being produced, so get this one before it's gone forever!

There are no original instructions, but I have generic written instructions I'll include, as well as a video tutorial.