Figure skating jumps
Jumps are referred to by how many times the skater turns in the air. One revolution (one and a half for the Axel) is a "single" jump. Two revolutions (two and a half for the Axel) is a "double" jump. Three revolutions (three and a half for the Axel) is a "triple" jump. Four revolutions (four and a half for the Axel, although this has never been done in competition) is a "quadruple" or "quad" jump. The first triple jump landed in competition was a loop jump. It was landed by Dick Button in 1952. The first quadruple jump landed in competition was a toe loop jump. It was landed by Kurt Browning in 1988. Currently, men in world-class competition usually attempt a full set of triples and sometimes one or two quadruple jumps in their free skating programs. Triple Axels are rare for ladies, and quadruple jump attempts even more so.
Quadratrix of Hippias
The quadratrix is mentioned in the works of Proclus (412–485), Pappus of Alexandria (3rd and 4th centuries) and Iamblichus (c. 240 – c. 325). Proclus names Hippias as the inventor of a curve called quadratrix and describes somewhere else how Hippias has applied the curve on the trisection problem. Pappus only mentions how a curve named quadratrix was used by Dinostratus, Nicomedes and others to square the circle. He neither mentions Hippias nor attributes the invention of the quadratrix to a particular person. Iamblichus just writes in a single line, that a curve called a quadratrix was used by Nicomedes to square the circle.