What is Spider layout?
The Spider is a layout of 108 tiles drawn as a spider seen from above. Its head, body and abdomen run down the middle of the board, stacked up to four layers high over the abdomen, and four long jointed legs reach out on each side, each a staggered chain of seven tiles.
The rules are the standard ones. Take off two matching tiles at a time, as long as both are free: nothing lies on top of them and their left or right side is open. Clear the board to win. With 108 tiles nine of the set's groups of four matching faces are left out, chosen at random for each deal, so every face still comes in whole pairs.
With 54 pairs it is the shortest layout here, three quarters of the Turtle. Most of the tiles lie flat in the legs, so the board shows most of its faces from the start; the work is untangling the legs, where the staggered tiles block their neighbours, and opening the stack on the spider's back.
Rule changes
| Rule | Standard Mahjong Solitaire | Spider layout |
|---|---|---|
| Layout | Standard Mahjong SolitaireThe Turtle: a broad block of tiles that rises in steps towards the middle. | Spider layoutThe Spider: head, body and a stacked abdomen down the middle, four jointed legs on each side. |
| Tiles | Standard Mahjong SolitaireAll 144 tiles of the set: 72 pairs to take off. | Spider layout108 tiles: 27 of the set's 36 groups of four matching tiles, so 54 pairs to take off. |
| Layers | Standard Mahjong SolitaireFour layers: 82, 40, 18 and 4 tiles. | Spider layoutFour layers: 89, 14 and 4 tiles, with one tile on top. |
| Free tiles at the start | Standard Mahjong Solitaire32 of the 144 tiles. | Spider layout31 of the 108 tiles. |
| Other options | Standard Mahjong SolitaireShuffles, a time limit and the random deal can be added in the setup. | Spider layoutThe same options work on the Spider: shuffles, a time limit and the random deal. |
History
Mahjong Solitaire began on a computer: Brodie Lockard wrote it for a university computer system in 1981, and a commercial version made it widely known in 1986 with a single layout, the Turtle. Later versions let players choose among layouts named after the shapes they draw.
A widely used version from the late 2000s offered six layouts: Turtle, Dragon, Cat, Fortress, Crab and Spider, each a stylised picture of its subject. Spider layouts have stayed popular, but no two programs draw theirs alike, and there is no standard one. The Spider here is our own design.