This cube reveals its inside once it is solved. Just hide your secret message and a fragile glass vial with a poisonous gas which will be released, should someone decide to break the cube out of frustration instead of solving it (Please, please don't poison anybody, I'm just kidding ;-)).
Step 1: What you need
• at least 25 two millimeter cubes (22 for the Rubik's cube and three to make a rig, but you should get a few more, in case you mess up)
• Oskar’s Treasure Chest (from Mefferts)
• Wood stain
• Clear finish
• Hot glue gun
• Strong two component glue
• Phillips screwdriver
• Dremel (114 High Speed Cutter, a Sanding Drum and a 3 mm drill)
• Optional: laser cutter, but the graphics are easy enough, so you can just paint them on.
Step 2: Make the edge pieces
Take the edge pieces apart, they consist of three pieces. Glue two of those pieces together as shown in the second picture. Use a compass to mark a circle with a 3 cm radius, where you will have to cut later. Use the sanding drum of the Dremel, to remove all the excess plastic, until the pieces look as shown in the third picture. Now mark the same radius on the small wooden cubes as shown in the fourth picture. Make sure everything fits, than use hot glue to glue them together.