Today is Pi Day, because the date in American usage is 3/14, the first three digits of pi. I call it "American Pi Day" because in the UK (and most other countries) the date would be 14/3. This led me to thinking - could we designate a Pi Day with the UK date format? 3/14 would be the 14th month, which doesn't work. And 31/4 doesn't work either because April has only 30 days.
But what if we relaxed the date format somewhat, by allowing the numbers to wrap around to the next month or year? Then 3/14 would be the 3rd day of the "14th month", which would be the 2nd month of the following year, so 3 February. Or 31/4 would be the "31st of April" which is 1 May.
This relaxed method of specifying dates allows us to find more special dates than we can with the normal format. 11/11/11 (11 November 2011, in both formats, as well as the quite common yy/mm/dd format) was very special, but that pattern ends there, unless we use our relaxed notation, when we get:
22/22/22 22 October 2023
33/33/33 3 October 2035
44/44/44 13 September 2047
55/55/55 24 August 2059
66/66/66 5 August 2071
77/77/77 16 July 2083
88/88/88 27 June 2095
99/99/99 7 June 2107
And finally, we can even do 00/00/00 by counting backwards: this would be 30 November 1999.
