shape and color matching idea

I have an idea for a game where players play cards and try to place them next to each other to match color and/or shape to score points (like Qwirkle in a sense). The 1/2 partial shapes of differing colors will be on the edges of the cards and will be placed to form a grid (2x3 or 3x3).

Any ideas for what these shapes and colors could be? The game is more abstract than themed so I'm more interested in aesthetics to have something nice to look at by the end of the game. Thanks in advance.