Chasing waves

The white dog has found a game that he loves, chasing the incoming wavelets as the tide turns. He will chase that white froth as far as he can up and down the beach, until the wave exhausts itself. Then he barks at a new one and begins again. He looks so happy.

The black dog does not understand the rules or the fascination, so she sprints after him, trying to stop him racing too far away, trying to make him come back towards me- all to no avail!
She looks rather anxious.

But when she gives up and speeds back to me, our reunion is exuberant and full of joy.