Back in 1991, home computer games were still a bit on the primitive side. The CD-ROM hadn't yet been invented, so any game you wanted to play needed to fit on a reasonable number of 3-1/2" floppy disks. So simplicity was the thing; Tetris and Solitaire were big hits for precisely this reason.
So, in its own small way, was Tesserae. Created for the MacOS (System 7, although it works on MacOS 8 and 9 as well) by the small but determined company Inline Design, Tesserae is a single-player logic puzzle with an interesting dimension to it.
At the beginning, your playing board is a simple rectangle randomly filled with square tiles (tesserae). Each tile is colored red, yellow or blue and decorated with a circle, square or cross (for the benefit of those using black and white screens). You play by flipping any tile over a second tile above, beside or diagonal to it, thus "picking up" and removing the second tile from the board.
-- flip ->
_____ _____
| || |
| + || O |
|_____||_____|
||
\/
_____
| |
| + |
|_____|
Now, here's the catch: If the tile you flip lands on another tile, their colors (and symbols) combine. A red tile flipped onto a yellow yields an orange tile. Likewise, red plus blue makes purple, and yellow plus blue makes green.
-- flip ->
_____ _____ _____
| || || _ |
| + || O || |_| |
|_____||_____||_____|
||
\/
_____
| _ |
| |+| |
|_____|
If you flip a tile onto a tile of the same color, or onto an empty space, then there's no combination.
-- flip ->
_____ _____ _____
| || || |
| + || O || + |
|_____||_____||_____|
||
\/
_____
| |
| + |
|_____|
Combining all three produces a grey tile. You cannot combine the same color twice on one tile; so red can be added to green (yellow+blue) to make grey, but not purple or orange. Nothing can be added to a grey tile.
-- flip ->
_____ _____ _____
| || || _ |
| + || O || |O| |
|_____||_____||_____|
||
\/
_____
| _ |
| |⊕| |
|_____|
You normally can only flip one tile over a second if that second tile is red, blue or yellow. However, if the second tile's color "contains" the first, you can perform a flip and "lift off" that color. So flipping a red tile over an orange tile leaves a yellow tile behind. Likewise, flipping red over grey (red+blue+yellow) leaves green (blue+yellow), and flipping green over grey will leave behind red.
-- flip ->
_____ _____
| || _ |
| + || |+| |
|_____||_____|
||
\/
_____ _____
| _ || |
| |_| || + |
|_____||_____|
Your goal is to flip tiles repeatedly until only one tile is left, using as few flips as possible. Time is recorded, but is not factored into your score. This is easy enough on the first level, which is a rectangle tiled with only primary-colored tesserae. Later levels use more exotic shapes, such as an oval or a fat "X", none of which leave any blank spaces in advance. To make things trickier still, later boards will start you out with secondary-colored tiles (green, orange, and purple) and even grey tiles on the hardest boards.
Thankfully, the game allows you to undo your moves as often as you liked, although doing so provides no guarantee that you'll be any more successful the second time. Strategy involves working your tiles from the outside corners and edges toward the center, flipping tiles onto other tiles of the same color to eliminate two tesserae at once, and creatively moving tiles around the board to eliminate secondary- and tertiary-colored tiles quickly.
A freeware clone of the original Macintosh game, called "Shattered Towers", was widely available for Mac users at about the same time Tesserae was released. However, while it used the same basic gameplay, it lacked the advanced boards which made Tesserae worth continuing to play.
Tesserae earned special recognition from GAMES Magazine by making their Top 100 Games of the Year list for 1991, one of fourteen puzzle games to make the list. (3 in Three, another computer game by Inline Design, also made that year's list.) Despite this (admittedly niche) recognition, the game remained little more than a sleeper hit. Perhaps it was the lack of animation and speed -- Tesserae had more in common with solitaire card games than in single-player arcade games like Tetris.
Years later it was ported to Game Boy and Game Gear and sold by GameTek, but never re-developed or improved upon for later Macintosh users -- version 1.0.6 was the last release, an update for compatability with System 7.5. The only DOS/Windows versions were written unofficially by fans of the game. However, a port was recently written for the GNOME interface for Linux; the (final?) stable 1.4.0 release was completed on July 10, 2001.