The dungeon floor is a 3-D volume — one axis more than a normal top-down floor. Each panel is a flat slice of that volume passing through you: XY (collapses z), XZ (collapses y), YZ (collapses x). Moving drives the two axes of the gold panel; the third axis only changes when you switch panels and walk there.
Collect 3 gems ◆, then step on the gold exit. Sparkles ✦ mark treasure hiding one slice away. And watch for a shimmering crack: some walls are only one voxel thin — solid in one slice, a single sidestep away in another.
The colored panel edges are the six faces of the dungeon box — same color = same face, so the three slices stitch together. Rule: an axis' + face wears the axis color (x/y/z = red/green/blue), its − face the complement (cyan/magenta/yellow). Floor tiles blush with those same hues when the voxel one slice + or − is also open — a faint, systematic "you could step through here". The bottom-right volume map shows the whole dungeon with your three slice planes floating inside it.
— press any key to descend —
All 3 gems recovered — that took moving through x, y and z. A true 4D burglar.
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— press R to run it again —