I found an antique perpetual calendar calculator that can tell you which day of the week it was or will be. : r/interestingasfuck
Wooden Desktop Perpetual Calendar w/ World Time Clock Calculator - CC-561W (China Manufacturer) - Other Stationery - Stationery Products -
White Vinyl 2-Wheel Perpetual Calendar & Scheduling Calculator (6" dia.) 4CP on front / Digital Black on back. | ArtechPro - Manufacturing promotional items
100 Year Perpetual Calendar + World Time Calculator Stunning 2" Brass Keyring : Amazon.co.uk: Stationery & Office Supplies
Perpetual Wooden Kids Calendar - BLUE GINKGO
This automated perpetual calendar is a beautiful way to watch the years pass by | Arduino Blog
Solid Brass World Time Zone Calculator and Perpetual Calendar Paperweights. Stanley London.
Durable LCD Calculator with Alarm Clock World Time Perpetual Calendar Functions (Color : Black) : Amazon.ca: Office Products