Can you count to three? That's all you really need
for these nifty mazes. Step, step, step, change colour, repeat.
Each visit to each group of coloured stones must involve exactly
three steps, no more no less. These mazes were designed during 2011
in collaboration with Robert Abbott (www.logicmazes.com).
These mazes were designed an atypical way. By following
a few basic ground rules (regarding the shape and size of the colour
groups) it turns out that a remarkable number of grid arrangements
naturally yield good mazes, requiring little or no refinement. A
key underlying reason for such a high yield is the relative ease
of arranging the grid such that the resulting state-diagram is fully
connected (all states are both reachable and escapable) despite
also being a directed graph (where moves are non-reversible). This
type of state-diagram is technically known as a strongly
connected digraph which, perhaps not surprisingly, turns
out to yield some very nice mazes.
(USA) features a stepping-stone maze entitled Three Flask Task
on its cover (March 2012 issue).