[whywhywhywhy]

OS X was never an X it was a roman numeral 10 and when used on its own it was mostly serif.

Pretty sure apples own presentations used “OS Ten” not “OS Ecks”

[foooorsyth]

But users definitely said “OS Ecks” and “iPhone Ecks”. Using X to represent 10 is a branding disaster. Doesn’t matter if you get it straight in your keynote that only nerds watch.