It tells you what day of the month it is retard
It means your period came at different times of the month, nothing more mystifying than that - when your period is due isn't determined by the date on the caldendar, it is determined by your menstrual cycle.
P. K. Shaw is not a well-known figure in history or literature. It is possible that the quotations attributed to P. K. Shaw on desk calendars are from a lesser-known author or a fictional character created for inspirational or humorous purposes. Without further context or information, it is difficult to determine the exact identity or significance of P. K. Shaw in relation to these desk calendar quotations.
There is a five-week month in the Gregorian calendar system approximately every 11 years. This occurs when a month begins on a Friday and has 31 days, resulting in five Fridays, Saturdays, and Sundays in that month. The last time this happened was in August 2021, and the next occurrence will be in January 2027.