Yukon Classic Challenge

Yukon Classic Challenge is one kind of solitaire games.
As other solitaire game, you can build up the card from Ace to King. But in Yukon, you can build down in alternating colors.
Ranking of cards is not continuous: an Ace may be built only on a 2, not on a King.
Any face up card, no matter how deep is in a column, may be moved to make a build.All covering cards are moved with it as a unit.