An image showing

Three sets of foot prints, on a pristine empty beach. The clear blue sky is reflected in the warm waters of the Caribbean Sea, wave lapping the beach. A green tree line made of palms separates the yellow of the sand from the blue of the sky. Maybe sometime soon you should add your own foot prints?    

An alternative description 

What a coincidence, how could it happen? The three of us, on the same beautiful palm lined empty beach, just what are the chancers. But you did not even notice me, or you chose not to. I walked right past you and you did not see me. You and him so completely engrossed with each other. How did we get to this?

All that’s left of us now are the passing foot prints in the warm sand. But by dawn the crystal-clear water will have washed them away and we will be no more.