Alternation takes the deal that gives Interchange its name — seven columns of seven with every second row face down — and builds it the way most players expect a solitaire to be built: down in alternating colours, a red 6 on a black 7. Any card may enter a space, a packed run moves as a unit, and the stock is turned once with no redeal. It sits between its two siblings in difficulty: looser than Interchange's suit build, stricter than Breakwater's rank build. Free in your browser, no sign-up.
Goal: build all eight foundations from Ace to King by suit.
The colour rule halves what each column top will accept compared with Breakwater, so the hidden rows are harder to reach and the order you dig them in matters more.
Three games share this deal in PySolFC's source, and they differ only in what may build on what and what may enter a space: Interchange builds in suit with Kings into spaces, Alternation in alternating colours with any card, Breakwater by rank with any card. Play sites tend to use the name Alternations for the rank-building version and note the colour rule as an option; this catalogue follows the registered source, so the colour game is Alternation and the rank game is Breakwater.
The alternating hidden rows are what make all three worth the trouble. Unlike a Klondike staircase, every column here hides the same number of cards at the same depths, so the game is about choosing an order rather than clearing the shallow columns first.
Like every game in this family here, the first stock card is left for you to turn rather than dealt to the waste at the start.
Two rules. It builds down in alternating colours rather than down in suit, and any card may enter an empty column rather than only a King. The deal, the run move and the single pass through the stock are identical.
Only the build rule: alternating colours here, any suit there. Both take any card into a space and both hide the same twenty-one cards. Breakwater is the easier of the two because each column top accepts twice as many cards.
The name has been used for both readings. PySolFC registers the alternating-colour game as Alternation and the rank-building game as Breakwater, and this catalogue follows those registrations so that each name means one game.
Yes. The source gives Alternation's row stack an open base, and the play sites say the same. Interchange's king rule does not apply here.
Twenty-one — three per column, in the second, fourth and sixth positions. Each turns face up automatically the moment the card covering it is moved away.
No. The 55 stock cards are turned once, one at a time, and the stock does not come back.