This looks pretty cool, but (to me) it would be way easier to understand if there was a square-on picture with thumbs in place, showing how to read the visible parts of the card.
I've been working on a simple calendar app too that is based on this layout. I find the layout cleaner and simpler to comprehend time passing over a year.
I had a Casio calculator that could show calendars like this. It could also play do-re-mi when you pressed digits and you could set an alarm with a jolly tune. And when I pressed the square root key repeatedly, the number got smaller and smaller until it showed 1. This was the 80s and it was my most precious thing.
As far as I can recall, the only time I need to know day-of-month is when scheduling and I need my actual calendar with existing appointments for that.
I dunno, it sounds like the kind of thing someone with a filofax would have in their wallet, same energy as a slide ruler, conversion tables on paper, etc.
I learned this years ago and it is life changing. It can be used to figure out the day of the week of any day in a couple seconds.
For example, the rule immediately tells me that Boxing Day is a Tuesday[0], so I know Christmas falls on a Monday this year.
[0] as does 3/14, 4/4, 5/9, 6/6, 7/4, 7/11, 8/8, 9/5, 10/10, 10/31, 11/7, and 12/12 since those anchor points are always on the same “doomsday”. Based on that, any day is just a little bit of addition/subtraction.
Your thumbs run vertically along the sides of the card, parallel to each other. You use them to cover anything to the sides of the month header(/footer) you're looking at. I think it's that "not under or above" description from the link that's confusing.
Find the header/footer for the right month. Use your thumbs to cover everything to the right or left.
Not if you put them to the right and left of the month's label. That's the whole point. The thumbs cover everything to the right and left of the label.
Around two years ago I was looking for a nice calendar on Amazon, but then I decided to just try to print one out. Since then I've been printing my monthly calendar and use it as a sort of logbook. It doesn't contain future things I need to be reminded of, I use Google Calendar for that.
