Christiaan Huygens... determined the mathematical formula that related pendulum length to time (about 99.4 cm or 39.1 inches for the one second movement) and had the first pendulum-driven clock made. The first model clock was built in 1657 in the Hague, but it was in England that the idea was taken up.[38] The longcase clock (also known as the grandfather clock) was created to house the pendulum and works by the English clockmaker William Clement in 1670 or 1671.

Work for 35 min

P1: 1.000 m row

P2: 20 Rotating KB Swings

20 Box hop overs

20 Rotating Wall Climbs

20 Rotating Burpees