A year consists of 12 months of 30 days each, divided into three décades of 10 days - each, followed by 5 complementary days (6 in leap years).
-The year starts on the day of the autumnal equinox at the Paris Observatory (longitude 2°20′14.03″ E). A - leap year follow directly from this definition: a year is a leap year when the next autumnal equinox - happens 366 days later instead of the normal 365. By this definition, the year will never drift - with respect to the seasons.
-The 12 months are: Vendémiaire, Brumaire, Frimaire, Nivôse, Pluviôse, - Ventôse, Germinal, Floréal, Prairial, Messidor, Thermidor, - Fructidor. Every three months represent a season, and the endings of the names reflect this - fact.
-The complementary days are: la Fête de la Vertu, la Fête du Génie, la Fête du - Travail, la Fête de l'Opinion, la Fête des Récompenses, and la Fête de la - Révolution (leap years only).
+The Tzolkʼin is composed from two concurrent cycles—the number 1 to 13, and a list of + 20 day names.
+The day name are: Imix, Ikʼ, Akʼbʼal, Kʼan, Chikchan, Kimi, Manikʼ, Lamat, Muluk, Ok, Chuwen, Ebʼ, Bʼen, + Ix, Men, Kibʼ, Kabʼan, Etzʼnabʼ, Kawak, and Ajaw.
+Note that the day name and number cycles are completely independent and advance concurrently. This means + that 1 Imix is followed by 2 Ikʼ and so on. There is no definite start or end to this cycle, but day + names repeat every 260 days, which is the least common multiple of 13 and 20.