This is a little-known variation of synaesthesia, in which the brain links one kind of sensation to another. Some people associate shapes with certain sounds, or colours with numbers. For some the year is a C stretching out in front of them, for others it’s a hula hoop.
The ways some people visualise calendars could shed light on memory itself
Emma sees time as a hula hoop, which anchors 31 December to her chest and projects the rest of the year in a circle that extends about a metre in front of her. December is the only time of year when the date in her mental calendar lines up perfectly with her body.
Heidi, another calendar synaesthete, sees the year as a backwards C hovering before her, with January at one end of the horseshoe and December at the other. When she thinks of a date she feels herself travel along the calendar to the right spot. She has a separate, hoop-shaped calendar for days of the week. Both have been part of her life for as long as she can remember.