The description in the NYT article sounds just like wall calendars.
From the article:
“The calendar pages are one-month pages with each day in a small box.”
That’s a wall calendar!
If the person quoted had seen a wall calendar, he/she would have described it that way. To me it sounds like he manually drew the boxes onto a sheet of paper. A guy this organized would do something like that.
I used to do things like that (the engineer in me) until tools like VisiCalc made it a lot easier to do on the computer.