this is the main effect:

ALL THESE FILES AND SOURCES ARE INCLUDED IN THE ZIP YOU WILL DOWNLOAD

this is an example of how it may be implemented. It requires a little more work, but the effect is worth it.

HOW TO:
1. I deleted the "dark side" of the cube. THe remainder will serve as MASK
2. I prepared the the flower to be placed under the MASK
3. I masked the flower with MASK
4. I placed the cube underneet the MASK/MASKED layers.