Children trundling hoops in the arena
Four children are each trundling two hoops, and turning around cones as they are used in an arena. Them wearing blue or green shawls refers to the Blues and Greens factions in the Constantinople area. Such scenes can often be found on Roman sarcophagi.
The museum's catalogue explains that hoop trundling was a serious sport for grown men too, and mentions several sources where it can be seen on monuments and such.