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.
It very much reminds me of a pentomino puzzle. Square board where you try to build certain shapes. I believe Tangram is a pentomino puzzle variant. Linked is an example of what I'm talking about (pieces are made of wood but you get the idea).
Good luck finding your game!