checking the ninth character of a vehicle identification number in your head
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.
Above each character is its weight, below a letter its number, then the product. The number on this sheet is only an example.
The letter numbers come from IBM’s EBCDIC code, where the letters run in three blocks: A…I are C1…C9, J…R are D1…D9, S…Z are E2…E9. A letter’s number is the last digit of its code. The third block, the right-hand column of the table above, starts at E2, so S is 2, not 1, and the cell above S is empty.
Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 3 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.
frame, wheel by ISO 5775 and handlebar — three signs of a class, and what the frame is rated for
segments A to F by length and bodies by box count — how to name any car you see
rake, trail, wheelbase and seat height — six classes drawn at one scale
nine lines of comparison, and in three of them the requirement is the same for both