Booby in the Wave Trough

• "Rockabaye Baby, in the Tree Top": a nursery rhyme originating in the 17th or 18th century. It is a lullaby. One version has the lines:

Rockabye Baby, on the treetops.
When the wind blows, the cradle will rock.
When the bough breaks, the cradle will fall.
And Down will come baby, cradle and all!

This song contains a fall and although sung in a sweet melody it is actually quite dark.

• trough: the lowest point in an alternating signal or wave. 'Trough' is the opposite of a 'crest' which is the highest point. If ALP is the trough then HCE is the crest (mountain).
• boobies: female breasts
• baby
• booby: a fool
• booby: one of a naumber of species of tropical seabird