Four decks lock all sixteen foundations to one random rank, so you're racing to fill eight tableau piles before the 39-card reserve runs empty.

Thomas Warfield scaled Canfield up to four decks here, so the foundations, reserve, and tableau are all bigger versions of the classic game.
If you enjoy Quadruple Canfield Solitaire, try Canfield Solitaire, the classic single-deck game it expands on, or Spider Solitaire.
If you run into anything odd or have an idea that would make the game better, please contact me.
Enjoy the game!
There are sixteen foundation piles.
One foundation pile is dealt a random starting card, which sets the rank for the whole game. The other fifteen piles fill in later, but only with cards of that same rank.
A card can be added to a foundation pile if it's one rank higher than the pile's current top card and the same suit. So the only card that can go on the 6 of clubs is the 7 of clubs. A pile can hold no more than 13 cards.
The top card of any foundation pile can move back into play if another pile will take it.
There's one reserve pile, dealt 39 cards to start. The top card is face-up; the rest are face-down. No cards can be moved into the reserve, but its top card can be played to the tableau or the foundation.
Eight tableau piles, each dealt one card face-up.
A card can be added to a tableau pile if it's one rank lower than the pile's current top card and the opposite color. So the cards that can go on the 8 of clubs are the 7 of hearts or the 7 of diamonds.
Any tableau card not covered by another card is free to play onto the foundation or another tableau pile.
An empty tableau spot is filled right away with a card from the reserve. If the reserve is empty, any card can fill the spot.
Sequences of cards running high to low in alternating colors can be moved together from one tableau pile to another.
There's one waste pile, and the remaining cards make up the stock.
Click the stock to deal three cards to the waste at once. You can go through the stock as many times as you like. Near the end of a pass, if fewer than three cards remain, whatever's left is dealt. The waste is then turned back into a new stock for the next pass.
The top card of the waste can be played to the tableau or foundation.