From 3blue1brown https://twitter.com/3blue1brown on Twitter: Pretty clever trick. Celcius is the percentage around a semicircle, Fahrenheit gives the angle (plus 32). This makes for handy intuitive conversions like 25C = 32 45 = 77F. 50C = 32 90 = 122F. Even handier if you're comfortable rounding 32 to 30. https://twitter.com/Photon_Sphere/status/1358170430922764288