It's also possible that some of these numbers have non-linear
relationships. For example Hectacomb with Amazons instead of Queens might
not be that much different in playablity in spite of the high PD
difference (aout 40%)--the PD is huge in either case.
Simiarly, assuming an 8x8 board, a game with 100 piece types might be
scarely less clear than a game with 50 (clarity approaching zero in both
cases), while 10 piece types vs. 5 makes an easily perceptible
difference.
It is also very possible that numerical criteria are best at comparing
games of somewhat similar types, and become more and more 'apples and
oranges' as the game types diverge.
The latter is why I objected to George comparing PTD in Fugue to PTD in
Chess. Compare it to Ultima and Rococo and it doesn't look so bad by
this criteria. It is by this measure less clear than Ultima or Roccoco
but the difference in not as extreme as the the difference with Chess.
