The Rules of Free Cell

This variant has been shamelessly borrowed from the Microsoft Windows 
entertainment package. The rules introduce a new pile type, which we call 
register or tmp. A register may hold only one card at a time, but this may be 
an arbitrary one. This is to compensate the fact that all cards are dealt at 
the start of game, which makes it very difficult to achieve a free slot.  The 
cards dealt initially do not often form valid groups. You have to rearrange 
them, possibly using the registers as scratch storage.  To get a free slot 
you have to build groups of cards which alternate in colour and have 
decreasing ranks.

The rules are easy to understand if you know Gypsy already since the rules 
for moving cards are the same.  Free Cell is played with one deck of cards. 
You have four registers, four stacks, and eight slots.