4 April 16

This is the fourth of (only) 12 square dates this millenium -- 9 each century if you use only two digits for the year. (This date is 4-4-16, and those digits can express 4-squared-equals-16.) The earlier ones were 1 January 01, 2 February 04, and 3 March 09. We have to wait nine more years for 5 May 25. I don't expect to be able to celebrate Square Day on 12 December 144. My tie has squares but you have to be willing to skew your world view to be sure.