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.
Cycloid
Constructing the tangent of the cycloid dates to August 1638 when Mersenne received unique methods from Roberval, Pierre de Fermat and René Descartes. Mersenne passed these results along to Galileo, who gave them to his students Torricelli and Viviana, who were able to produce a quadrature. This result and others were published by Torricelli in 1644, which is also the first printed work on the cycloid. This led to Roberval charging Torricelli with plagiarism, with the controversy cut short by Torricelli's early death in 1647.