Plank Puzzle No.15 - Fiendish
Fiendish was devised by hand over a period of several days. My sole aim was to improve on my previous best (Route-66) which I had stumbled on more by luck than judgement and was a big leap forward in its time. A nifty windows-based (C++) plank-puzzle editor/solver (by applet author, Graham) was used to verify the solution. Fiendish is actually shorter than Route-66, but more complex and compact, as (hopefully) illustrated in the following table.
During the first few heady months of plank puzzle exploration I fixed on the notion that the best way to measure plank puzzle complexity was by move-over-span ratio which is why I initially ranked Fiendish above Route-66. Until March 2001 Fiendish and Route-66 were the only two puzzles with a move-over-span ratio greater than 1 (meaning the number of moves actually exceeds the number of possible plank positions).
|Grid||9x9 (square)||8x8 (square)|
|Planks||3 (1+2+3)||4 (1+2+3+4)|
|Shortest solution||66 moves||57 moves|
However... In March 2001 Pascal Wassong well and truly smashed my move-over-span ratio record with a plank-puzzle of his own design entitled The Centrifugal Force (TCF for short). TCF requires an incredible 342 moves and has a move-over-span ratio of 4.62.
concept & maze design - © Andrea Gilbert 2000-2001
HTML5 implementation - © Jeremy D. Miller - 2017
hosted with permission from Jeremy D. Miller