This time of year, we become a bit obsessed with daylight, days, and calendars. The new year is just a manmade concept, an arbitrary place to start a new calendar, while the revolution of the earth around the sun is a concrete amount of time we can measure. However, when the days, weeks, months, and years don't line up with each other for a variety of reasons, people tend to "fix" the calendar to be more useful. That leads us to the different calendars used for different purposes. One of them is based on weeks for financial uses, and it has also been appropriated for computer coding, which leads to some weird anomalies. Tom Scott explains. Keep in mind this video was posted on December 30.