The Human Calculator on Twitter: "This is a zero-based 13-month calendar. There are 365 days divided into 13 months of 28 days. 13x28= 364. The extra day is the zero-day. There are
![The Human Calculator on Twitter: "This is a zero-based 13-month calendar. There are 365 days divided into 13 months of 28 days. 13x28= 364. The extra day is the zero-day. There are The Human Calculator on Twitter: "This is a zero-based 13-month calendar. There are 365 days divided into 13 months of 28 days. 13x28= 364. The extra day is the zero-day. There are](https://pbs.twimg.com/media/FIJJRqGXEAM_NHx.jpg:large)
The Human Calculator on Twitter: "This is a zero-based 13-month calendar. There are 365 days divided into 13 months of 28 days. 13x28= 364. The extra day is the zero-day. There are
![The Myth of the 28-day 13-month year. The Celtic Tree Calendar and (allegedly) others - Druidcraft Calendar The Myth of the 28-day 13-month year. The Celtic Tree Calendar and (allegedly) others - Druidcraft Calendar](https://druidcraftcalendar.co.uk/wp-content/uploads/2019/05/49237483_2196771217075617_8383332066468560896_n.jpg)