So, you wander across this sandy bit to the island, remembering of course to come back before high tide otherwise you end up doing a bit of improptu swimming/wading with your bag on your head. Ahem.
Once there you can player a game of checkers. Admittedly we had to improvise with rocks and shells, but you can’t have everything can you? Still, it did make for a somewhat more complicated game than usual. It had to be said some rocks were a bit, well, shell like and vice-versa. Cue large arguments about coral being a rock or a shell.