It has blocks in different arrangements- L shaped joined, three-in-a-line joined, single. Colours were red, blue and black. The objective of the game as I remember it was to put the tiles/ blocks together in different ways to make a pattern shown in a book that comes in the set, the over-all pattern usually contained in a square outline. Levels range from easy to hard, definitely a game that adults can attempt too. Someone said Tetris but it's nothing like that, although the blocks are similarly structured. Got this as a present when I was younger but I can't for the life of me remember what it's called.
edit: Comments below say it's a variation of Tangram and pentominoes and I think that sounds about right! Hopefully this image will help identify the name. 
