Leap year
The name "leap year" probably comes from the fact that while a fixed date in the Gregorian calendar normally advances one day of the week from one year to the next, the day of the week in the 12 months following the leap day (from March 1 through February 28 of the following year) will advance two days due to the extra day (thus "leaping over" one of the days in the week). For example, Christmas Day (December 25) fell on a Sunday in 2016, and Monday in 2017, then it fell on Tuesday in 2018, and will fall on Wednesday in 2019 but then "leaps" over Thursday to fall on a Friday in 2020.
Jewish Talmudic Calendar
The position of the years in a Small Mahzor is called the Golden Number. The pattern of the leap years will change slightly each Iggul, but the Jewish Talmudic Calendar fixd the leap years in the year with these golden numbers: 3, 6, 8, 11, 14, 17, 19. If we mark a Leap year as L, the Followship Year as F, and the Other common year as O, we have