I have number form synesthesia which is a mental map of numbers that “automatically and involuntarily appears” whenever I think of numbers. This is how my mental map looks, except the black background has white points of light on it like the night sky. I have the same thing with days of the week and dates in general. My mental calendar only has one right angle though, at 1900. Both the days of the week and the years on my mental calendar are upside down, like I am looking down at the list from above. The months of the year are more like a calendar with me looking at it from the side.
via Tumblr http://tumblr.soelo.com/post/61561714541