PalmIshido is a free (GPL), polished and challenging tile-matching puzzle game with multiple full-color high resolution (OS 5 required for high resolution) board and piece sets (default, hieroglyphic and Ugaritic pieces are included), based on the rules of Ishido. You place pieces on the board, one by one, beside existing pieces, hoping to get four-way matches. The rules for placing pieces are:

• If the new tile has only one neighbor, it must match it by shape or by color or both.
• If it has two neighbors, then one of these must have (at least) the same shape as it and the other must have (at least) the same color as it.
• If it has three neighbors, then either two of these must have (at least) the same shape as it and the other (at least) the same color as it, or else one of these must have (at least) the same color while the other two have (at least) the same shape.
• If it has four neighbors, then two of the neighbors must have (at least) the same shape as it and the other two must have (at least) the same color as it. This is called a "four-way".

Includes full source code.