At work we have to read and record part and serial numbers off of parts and when writing them down, we put an angled slash through the zeros to differentiate them from “Ohs”. If reading or telling others part or serial numbers ( ordering over the phone to a stock clerk ), many of them are formatted such that they have a series or sequence of zeros. In turn, instead of saying “…zero, zero, zero, zero…” the customary lingo is “…four balls…”.
A UPS tracking receipt I got recently was near indecipherable. Tiny, narrow characters made of dots. You couldn’t tell if it was a U or a V, a 2 or a Z, and trying to use it to track a package was futile (it got there anyway).