This is a 3-dimensional maze consisting of an array of both vertical and horizontal paths as well as side-way channels, no curves, but just like a real city subway system with all its levels, walkways and lifts. Although my copy came to me second-hand, the quality of construction and finish is very good.
This puzzle is very challenging since the clear layers of acrylic make it very hard to see the various paths, channels and openings clearly (no pun intended) and the disc being so small. For me, it was quite a bit of strain on the eyes. I fiddled with the puzzle for a pretty long time, dragging the disc all over the maze with the wand, trying to reach my destination but got nowhere.
The fact that the disc sometimes just froze at some of intersections of the the channels and openings didn't help either. Was it electrical static that caused the disc to get stuck now and again? I am not sure. In the end, I solved it by referring to the solution. I later discovered that playing with the maze in front of a computer screen in a dimly lit room showed up the maze's paths very much more clearly!
I asked Oskar why a magnetic disc was chosen (given the kind of difficulty I faced) instead of perhaps using a small ball bearing, which to me seems a better choice. Oskar replied that his original version was to use a ball bearing but implementing the disc was George's idea. Anyhow it was felt that the disc involved less dexterity and more control with the wand. Well, who am I to argue with Oskar anyway?
Not easy to solve given the maze design and materials used and also the requirement of the wand to move the disc around. I wish I could pry open the acrylic layers and replace the disc with a ball bearing but that would mean an irreversibly damaged puzzle. Nevertheless a uniquely themed maze and certainly a rare and collectible puzzle.