Click on the grid to toggle a square from water to land.

Black squares are water, white squares are land.

Adjacent groups of land squares form an island. Two squares are adjacent if they are horizontal or vertical neighbors. When 'Diagonal Islands' is clicked, diagonal neighbors are also considered adjacent.

Lakes are adjacent groups of water squares that are surrounded by land. Lakes are bordered in blue.

The number of islands and lakes is displayed.

The clear button resets the grid.

The reverse button switches all land to water and all water to land.

Click here for more information.