The phases of the moon work in 28-day cycles that are always repeating, with variation created by the moon’s orbit around the earth. This orbit results in differing angles of view for us of the ever-illuminated half of the moon’s surface. Standing on earth, the moon appears to cycle through a variety of shapes, the process of which is described in more detail here. All this variation occurs over periods of time that are not quite a month, so mapping these changes in a year-long calendar presents a unique challenge: how to align the pleasing visual rhythm of the moon’s changes with the familiar months and days for reference? The most elegant answer comes from graphic designer Irwin Glusker in the form of a poster he created for the MoMA Design Store. In a clean, black-and-white grid, which conforms to the months as rows and the weekdays as columns, the precise phase of the moon on every day of the year is immediately discernable. Remarkably, the design requires no written explanation and allows us to enjoy the visual repetition of the cycles which occur irregularly across the months, with no two quite the same.