PART II - MANY ANSWERS, NO WINNER
A Century of Martian Calendar Design

There is no shortage of Martian calendars.

For more than a century, designers have proposed twelve months and twenty-four, continuous weeks and perpetual dates, equal-time periods and seasonally expressive ones, familiar Earth conventions and deliberately Martian alternatives.

The disagreements are useful because Mars itself remains the same.

The planet has not changed between Levitt, Darian, Zubrin, Šurán, Hargitai or Exodus. What changes is the property each design chooses to protect when the arithmetic refuses to provide everything at once.

Strip away the individual calendars and five choices keep recurring.

Scale — what should the month preserve: annual position or familiar duration?
Week — which form of recurrence matters most: continuous weekly succession or fixed date–weekday relationships?
Representation — should civil periods favour equal elapsed time or stronger orbital and seasonal meaning?
Anchor — where in the Martian annual cycle should the civil year begin?
Interface — how much terrestrial familiarity should a Martian calendar preserve?

These are the Five Choices of Martian Calendar Design.

They are not entirely independent. A decision on one can constrain the others, and every attractive property tends to spend some of the calendar's design budget somewhere else.

Part II therefore treats previous calendars not as failed attempts on the way to Marian, but as experiments across this design space. Different designers make different choices because they are solving slightly different versions of the same problem.

Before proposing another answer, it helps to understand what has to be chosen.