The Symmetry010 Calendar (Sym010) is a proposal for Gregorian calendar reform developed by Dr. Irv Bromberg of the University of Toronto, Canada. It is a perpetual solar calendar that conserves the traditional 7-day week, and has symmetrical equal quarters of 30+31+30 days each. Unlike its sibling system and successor, the Symmetry454 Calendar, it does not start every month on Monday, but has month lengths closer to the traditional ones. It is retained as an alternative for those who think that the Sym454 design is too "radical" a departure from the Gregorian calendar format.