"Come To The Edge"

"Come To The Edge"
   I absolutely love this quote, which is widely attributed to Guillaume Apollinaire (1880-1918), a French poet / writer of Italian birth and Polish descent, was hugely influential as a Modernist poet and as a spokesman for the Cubist painters.
"Come to the edge he said.  They said, we are afraid.  Come to the edge he said.  They came.  He pushed them, and they flew."     I have made two other pieces using this quote, and I think many other people really like it too, because I continue to have more requests for it in my art.
   This scrabble tile art piece is constructed inside a wooden frame, covered in various tissues. The tiles are placed atop a cut portion of the lid of a wine box fitted inside the frame.  Six inches of vintage wooden yardstick finish the piece.  A colorful Mexican parrot, and a small brass bell, calls you to 'the edge'.
   One thing I have not been able to figure out about this quote is: What was Apollinaire referring to when he said this.  Do you know?  Share with me if you do.