Long term Gregorian calendar has two sections which can be rotated to find corresponding dates and weeks

摘要

The long term Gregorian calendar has two sections in seven panels connected by a rivet to allow the inner section to rotate inside the fixed outer section to find a precise day of the week corresponding to the date being searched. The outer fixed section can carry years, months and dates. The movable inner section can have centuries, the Fridays and the days of the week.