[llkdixos] 30-31 calendar

The calendar ought to have 30-day months alternating with 31-day months as much as possible, and the leap day ought to happen as the last day of the year.  Compared to the current irregular pattern of month lengths, this system would be easier to remember, more uniform, and less complicated to do calculations with.  On normal years, the months therefore ought to have lengths 30, 31, 30, 31, 30, 31, 30, 31, 30, 31, 30, 30 days (two consecutive 30-day months at the end of the year).  On leap years, the months obey a perfect pattern of alternating 30 and 31 day months, because (30+31)*6=366.

The best way to implement this is with new month names.  Month names should incorporate their number (as Japanese does it, as Latin presumably partially did at some point: September = 7, ... December = 10), so, to remember whether a month has 30 or 31 days, just test whether the month number is even or odd.  Number months from zero so that even-numbered months have an even number of days and odd-numbered months (except the last month on non-leap years) have an odd number of days.  Numbering from zero also simplifies calculations.  (Days within a month numbered from zero would also simplify calculations.)

Bad idea: Mostly alternating month lengths could also be accomplished with some ugly cut and paste on the current calendar because it already mostly alternates 30 and 31: Cut out August (currently the exception to alternation) and make it the first month, inserting it before January.  Shorten August in its new location to 30 days (because shame on Emperor Augustus for breaking the pattern of 30 and 31 days).  December gets 30 days on normal years, but 31 on leap years.  February is lengthened permanently to 30 days.  The month names do not have their number as part of their name: August=0, January=1,... July=7, September=8, October=9, November=10, December=11.  January is no longer the doorway from the old year to the new.

All this assumes we keep a 12 month calendar.  Previously, 7 months and other variations.

10 months seems attractive given our love of base 10.  Perhaps we shouldn't call them "months" because there would no longer be any connection to the moon, though our predominantly 30 and 31 day months have already long since abandoned synchronization with the moon.  10 deciyears in a year.  Five 37-day deciyears alternating with five 36 day deciyears is 365 days.  The last deciyear becomes 37 days instead of 36 on leap years: two consecutive 37-day deciyears at the end of a leap year.  Assuming we number deciyears starting from zero, it's slightly annoying that even-numbered deciyears have an odd number of days and vice versa.