"wave" is a good guess, but it's not the one. What does a beach full of sunbathers and swimmers represent?
Sorry, off topic, but does plonka mean idiot or stupid? *Has to keep up with her English vocab so she knows what the heck is going on*
Not too far off, Matthews! Perhaps this is only a well known phrase if you're an ardent follower of Girls Aloud
I was going to say 'Long Hot Summer', but I couldn't see how 'Long' fitted with fig.1. Long Hot Summer