This is a more difficult version of the well known FreeCell game. It also should be considered related to Bakers 6.
The name SixByFour appears to allude to the 6 tableau columns and 4 reserve piles. An Open style game, all of the cards are dealt face up into the Tableaus and it is your job to order them into the foundation. As in FreeCell, card play in the Tableaus is alternating color, and you can move matching piles. And any single card may be moved (temporarily) to one of the four Reserve piles to help you out. Because SixByFour eliminates two of FreeCells Tableaus the cards are more buried and you have less flexibility, so SixByFour helps you a little by letting you play any matching sequence into the elusive empty tableau space.
I found this variation on the Internet (Goodsol).