The 12-cent Perpetual Calendar

It’s Wednesday, the fourth day of the week. The binary number for 4 is 100. We use “heads” for 1 and “tails” for 0. So the left hand column has (top to bottom) heads-tails-tails = 100 binary = 4th day of week = Wednesday. (If you don’t already speak binary, no biggie. Start here or here and join us in a minute.)

It’s December, month 12, and 12 in binary is 1100, so the middle column is heads-heads-tails-tails.

Finally, the last column is all heads, since it’s December 31, and 31 decimal = 11111 binary.

Got that? Me neither. Link