The author remixed this model.
Added pockets for 5mm x 3mm magnets to make the tower hold together stronger. The fit is very tight, so make sure you put the magnets in the right way! You'll probably have to destroy the block to get them out. You may need a gentle rubber mallet tap to get them in.
I put the two magnets next to the strategy name holder North-Up, with the other South-Up, so the stack will be aligned.