This is Double Squares by Manfred Kopp in 1992

You have a 10 x 10 Grid in front of you, and you need to set as many tiles on the board as possible, each tile has an inner and outer square, upto 10 different colours, The Game can also be played with 1-2 players

You can only place the tiles in squares if there is no other tile with the same inner or outer colour, luckily the game shows you all possible positions you can place the tiles, which show as inverted squares

The game will end when you have placed all the tiles, or your timer runs out, Can you fill the grid or will you fail?

Interestingly, There is the Full Version included, But I do not know its password, You have a Decode program, and once you paid the Shareware fee, You would get the password to enter into that program so you could Decode the Full Version, which is quite a good idea, as this saved shipping disks out to everyone who had registered

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Code: Manfred Kopp