Pentomino is a puzzle game released for Windows 3.x in 1992 by Quanta Press. The object of the game is to place blocks into a puzzle so that the entire perimeter of the provided shape is covered; as the puzzles are solved, a picture is revealed behind them.
Pentomino begins with 16 cut outs obscuring a picture; by clicking on each of the cut outs, players can begin a the mini-puzzles. When the puzzle is solved, the cut out is removed revealing the section of the picture behind it. In order to reveal the complete picture, all 16 of the mini-puzzles need to be solved.
Each of the mini-puzzles consists of a particular shape made out of blocks; the goal is to place additional blocks along the complete perimeter of the shape which is indicated on the screen by a shaded area. The game provides blocks of varying sizes and shapes which can be dragged from the bin on the right side of the screen into the puzzle area on the left; The blocks can also be rotated before being put into place, and it may not be necessary to use all of the blocks provided. While it is possible for blocks placed in the puzzle to extend outside the border, some puzzles don't provide enough pieces to do this. Once the complete shaded area has a block placed in it, the puzzle is complete. Puzzles of various difficulty levels are included; the simpler puzzles have more basic shapes and provide extra blocks to place while more difficult puzzles have large, complex shapes and don't have many extra pieces to work with. The game allows progress to be saved so players can continue at a later time.