The Voice of Vexillology, Flags & Heraldry

Saturday, March 14, 2026

Happy Pi-Day! We have another Pi-Day flag based upon the old UK numerical flag numbers at the turn of the century. There have been a lot of changes with the UK numerical signal flags, but this one based upon the numbers at the turn on the 20th century. Namely 3, which had a blue and yellow checker pattern, 1, which was a red and white checker pattern and 4 which was the rare horizontal blue, white, red flag that never seems to stick. They always prefer red on top and blue underneath!

Kriegsmarine π-Day Flag, Using the Old German Numbers

The Kriegsmarine, old German, π-Day flag utilized the old numbered flags used by Germany before the end of the WWII. The number 3 takes up most of the space and is conserved, except for in the middle. The number 1 is the red diamond with the two white stripes, and in the center is another diamond taken from the flag for the number 4.

The German marine Pi-Day flag just happens to look like something of periscope by coincidence, as and the white stripes give it a wolf like fang appearance, which was so appropriate for the German U-boats 'wolf packs' that were active during WWI & WWII.

The German/Kriegsmarine Naval Signal Flags 0 to 9 is the basis for the German π-Flag

π-Day Resistor Flag - Resistance is Futile: 3.14 forever!

The Pi-Day Resistor colour coded flag is orange, brown, and yellow. The color orange represents #3, brown represents #1, and yellow #4. The ratios are uneven to represent each numbers relative value. Remember, its 1/10th so a smaller brown section, and 1/100th is the small yellow section for #4.