This is the first piece that I wrote using a tangram puzzle. 
I arranged the puzzle by putting the same colour groups together on each of the four squares (orange and red, light greed and dark green, turquoise and blue, light purple and dark purple). Two different blocks form a rectangle along the puzzle.
Each colour represents a pitch, and the distance between the pitches of a same group colour (i.e. red-orange) is either a tone or a semitone. The idea of the piece is to have trills or tremolos between both the pitches of each rectangle.
The piece has four movements, each with different colour combinations, which get more varied and complex on each movement. By changing the blocks on the puzzle, new trill combinations of trills are obtained.