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Date: Tue, 3 Jun 1997 12:57:16 -0700 (PDT)
From: Don Woods <don@clari.net>
Message-Id: <199706031957.MAA14492@madrigal.clari.net>
To: cube-lovers@ai.mit.edu
Subject: Re: FreeCell
Cc: ad@dcs.st-and.ac.uk

> Could someone describe the FreeCell puzzle for us non-windows people?

This is perhaps getting a bit off-topic for cube-lovers, since FreeCell
is a card game, but it can also be thought of as a puzzle in which you
are to unscramble a randomised bunch of cards, so maybe it's not so far
off-topic at that.  Anyway, since you asked:

Shuffle a standard 52-card deck and deal them out to form 8 columns of
cards; 4 columns of 7 and 4 columns of 6.  All the cards are face up,
and you should spread the columns (while keeping the cards overlapping
within each column) so you can see all the cards.

Above the columns are 8 initially-empty spaces.  4 of these are reserved
for collecting the 4 suits in order: the object of the game is to move
Ace-deuce-3-4-...-queen-king of each suit onto these spaces.  The other 4
are "free cells": each free cell can be used to hold any SINGLE card.

You move only one card at a time.  The only cards you can move are the
last card of a column (i.e., cards that don't have other cards on top
of them) or a card in a free cell.  A card can move to (1) an empty free
cell, (2) an empty column (i.e., a column where you've moved out all of
the cards), or (3) a column whose last card is the opposite color and
one rank higher than the card being moved (i.e., you can place a red 6
on a black 7, etc.).  A card can also be moved to the suit-collecting
piles if it's the next card needed in that suit, i.e., an Ace to empty
suit spot, a deuce onto the Ace of the same suit, etc.

The Windows version of the game lets you specify a number and then
generates a deck based on that number, so you can get the same initial
layout by giving the same number again.  Thus it offers only a small
fraction of the possible layouts.  I wasn't part of the effort that
solved the Windows layouts, but I did write a program to solve FreeCell
layouts and fed it a million random layouts, and it solved all but 14.
So I don't find it surprising that all but 1 of the 32000 Windows
layouts is solvable.

There are several other puzzle-type solitaire card games with a similar
theme.  E.g., Seahaven Towers uses 10 columns instead of 8, and two of
the free cells start with cards in them (each column has 5 cards).  In
Seahaven Towers, moves onto a column must be matching suit instead of
opposite color, i.e., 6 of clubs onto 7 of clubs.  Also, only a King
can be moved into an empty column.  Thus the moves in Seahaven Towers
are much more restricted; my program for that game runs a lot faster.
About 90% of Seahaven Towers layouts can be solved.

	-- Don.

-------------------------------------------------------------------------------
-- 
-- Don Woods (don@clari.net)		        ClariNet provides on-line news.
-- http://www.clari.net/~don		        I provide personal opinions.
--