I'm sorry. I can't show you the location of these secret compartments or they'd no longer be secret!
But I will tell you that they are made using metal springs, wood springs, magnets, false walls, sliding panels and compartments within compartments.
I put secret compartments in most of my pieces.
Look at the bookcase below and see if you can guess how many secret compartments are contained in this piece. (see bottom of page for the answer)
answer: 14!