From the song "The Ballad of the Shape of Things to Come" (lyrics link):
Triangular is the piece of pie I eat to ease my sorrow
Triangular is the hatchet blade I plan to hide tomorrow
Triangular the relationship which now has ceased to be
And triangular is the garment thin
That fastens on with a safety pin
To a prize I had no wish to win
It's a lasting memory
That my true love gave to me
I'm a non-native speaker, and the meaning is unclear to me. What could be this "garmet thin" of triangular shape? And what is the "prize I had no wish to win"?
I feel that the two might be related so I clumped them into a single question.
P.S. Who is the author of the ballad? I haven't found the author. The Kingston Trio?