Thank you. I will definitely make a ring wall - that's the main thing that makes it feel 3D and different from the playmat, I think. I just don't have any styrofoam to make it from at the moment, so it will have to wait until I can source some.
I'm a sucker for symmetry, so this is the layout I have drawn up for where the magnet zones are. So far there are seven, although I suspect I will end up with nine in total. You can see that the tiny dots within the darker zones are the actual magnets.
I like that I can make the setup symmetrical with any number of a single hazard piece types this way.
With only one of a certain type, I can put it in the middle.
With one, two or three sets of two, I can place them across from each other.
With one or two sets of three, I can put them in a triangle shape.
With one set of four, I can put two on the left and two on the right.