Relay

How?

13 musicians
3 locations
at 13 minutes past 2 o'clock
a trio begins playing in each location
after some minutes the remaining 4 set out
when a player comes into a location and starts playing
another must leave
so there are only trios
the leaver goes to either of the other locations

...continue for 3 hours

Where?

Who?
for participants in all Relays click on places
(including the especially excellent gallery of musicians' self-portraits - in 'england')