At the bottom of the diagram is the sea bed, with a shipwreck embedded in it. Above the sea bed is a blue area, representing the sea, and on the upper surface of this is a ship, floating on the sea surface. Below the ship is a shape labelled 'sender / receiver'. Red curves, labelled 'original wave' spread out from this and head down towards the sea bed. White curves, labelled 'reflected wave', spread out from the bump on the sea bed above the shipwreck and head up towards the sea surface.