The tricky part about this achievement is in getting the two hypercubes next to each other so that you can use one on the other.
My approach was to keep making them at every opportunity and eventually got lucky creating one in a vertical pattern right above another one.
If at all possible try not to use them and you may get lucky in the transition between levels.
You also need to remember to keep them out of the line of fire of other special gems.
Good luck :-)
According to Kennansoft completing this will not unlock the following achievements :-