- Circles grow at a constant rate.
- No two circles can overlap.
- Bigger circle pushes and shrinks smaller circle when in contact.
- A circle “pops” and makes a sound when its boundary intersects with the center of another circle.
- The pitch of the sound is determined by the position of the circle on the background. Bigger the hole, higher the pitch.
- The envelope of the produced sound is determined by a number of parameters including final circle size and time of interaction between two involved circles.