Shanghai solitaire

Shanghai solitaire (also known as electronic mahjong) is a three-dimensional solitaire matching game that uses the tiles[?] from a mahjong set rather than cards. The 160 tiles are arranged in a special four-layer grid with their faces upwards. Exposed pairs of tiles are removed from the grid one at a time, gradually exposing the lower layers to play. The aim of the game is to clear the grid by pairing up all the tiles. The game is finished when either the grid is empty, or there are no exposed pairs remaining.

There are 4 suits in the tile set -

circles or coins (nine values, with four tiles of each number)
bamboos or bams (nine values, with four tiles of each number)
characters (nine values, with four tiles of each number)
honors - comprising
- four winds (North, South, East and West) (four tiles for each wind)
- the four seasons (Spring, Summer, Autumn and Winter) Unique tiles that function as a set
- the four flowers (Orchid, plum, chrysanthemum, bamboo) Unique tiles that function as a set
- the three Dragons (red, white and green) (four of each dragon)

While Shanghai solitaire can be played using genuine tiles and a special wooden frame for set-up, it is usually played in an electronic form as a computer game. This removes the tedium of the set-up process and the temptation to cheat. Some electronic shanghai games offer extra options, such as the ability to change the tile set and patterns from the traditional tiles to flowers, jewels or some other item that may be easier to match up at a glance, to play a series of different layouts with increasing levels of difficulty (usually given chinese names such as 'the ox' or 'the snake'). These games also have an optional time limit, and offer hints/cheat options such as the ability to have a match found for you, or to backtrack and undo already made moves if the game isn't working out.

Shanghai can be played either solo, or with a partner in which case the aim is either to accumulate the most pairs, or to be the last one to match a pair.