In this calendar, the Y-axis represents time, with the path of the Moon, Earth, and Sun traced as they move through space and time. The corresponding date of the calendar is set at the right, and acts as a unit for graduation lines.
Though the exact curves and positioning of the planets aren't 100% accurate, it is still clear that the Earth makes one full rotation around the Sun as the moon makes multiple cycles around the Earth.
In this form, it makes it a bit easier to comprehend the relative rate of rotation between the planets. Even a quick glance makes the patterns in motion easy to see; patterns that are invisible in a standard box-based calendar.
The decision was made to keep the background white, as opposed to the standard black of space, to allow for writing on the calendar.
Though totally different in it's final form, the idea for my planetary calendar was sparked after seeing this illustration by Buckminster Fuller which traces the path of the planets over time through their rotations