1 to 12 · colour intensity = size of the product
Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.
Three sizes in one archive — from a sheet on the fridge to a poster on the wall.
Row and column meet at the product. The outlined diagonal holds the square numbers.
It looks like 144 facts. Let’s count honestly how many there really are.
The table mirrors itself: 7×8 and 8×7 are one fact, not two. That leaves 78.
The 1, 2, 5 and 10 rows come for free. Drop them and only 36 genuinely hard ones remain.
Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 4 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.
