collection of puzzles for X (plain X version)
The following puzzles are included:
 - Rotational 3D Puzzles: xrubik, xpyraminx, xoct, xskewb, xdino,
                          xmball, xbevel
 - Sliding Block Puzzles: xcubes, xtriangles, xhexagons, xpanex
 - Combination Puzzles:   xbarrel, xmlink