The story: it is about an atomic particle that wants to convey it’s love for Earth by writing in the sky. It can do it by tweaking the magnetic field so particles will line up and form a shape. The shape should convey the message, so it should be some universal symbol for love.
About the program: for shape recognition the program takes random samples of particles to trace the pattern they fly in. Because it is random it is advisable to make alle particles fly in the same path, otherwise particles may be sampled that are for instance still flying in circles.
Read on if you want to know what shape to go for, but I recommend to play the post-compo version: It gives you messages about the shape in game. The rest of the game is the same.