Curling the curl comes from a physics problem that involves dropping on a rail that has a perfect circular turn, a weight at a certain height and that it can turn all the way without falling. It has been proven that there is a minimum height to release the weight so that you can perform the full turn without falling. It is also an eye-catching luck in aerial exhibitions, where a plane takes a complete turn in the air leaving headlong at any given time. The gringos say "loop the loop". It is used in colloquial language as a metaphor for finding the optimal point to solve a problem.