Playing with Rounds is like being 4 singers all at once each doing his/her part in "Row row row your boat." Players are challenged to click each of four tune icons so each voice comes in on time. If successful, players hear a 4-part counterpoint piece like Mozarts Bona nox and others.
You can play all four people "singing" Row Row Row Your Boat. You just have to click on the next icon when each person should come in. Lots more Rounds to play, too. Each voice can play in a different instrument.