Usage: puzzle [--configs] initial...

--configs: search and time solutions with various configurations of solvers.
initial:   an initial configuration (letters for the tiles, and dot for the hole). eg:

 8-puzzle:

 goal (0):    abcdefgh.
 easy (4):    abce.fdgh
 medium (10): eabf.cdgh
 hard (20):   feacbh.dg
 harder (31): hfgbedc.a

 15-puzzle:
 goal (0):    abcdefghijklmno.
 easy (30):   bacdefghijlkmno.
 medium (40): fg.jacoheldnibmk
 hard (55):   kleg.mondcafjhbi
 harder (61): lomgkcend.afjhbi

 24-puzzle:
 goal (0):    abcdefghijklmnopqrstuvwx.
 easy (55):   giabcjekmdhrtflqsownpuv.x
 medium (75): giabcjekmdrtwulhs.vnqofpx
 hard (79):   giabcjekmdrtw.uhsvnlqofpx
 harder (80): giabcjekmdrt.wuhsvnlqofpx