From what I remember from college, the 10th falls in a symmetrical line of semitones. Don't quote me though. College was almost 50 years ago and I am having more and more days when I don't remember where my car is when I come out of Walmart.

My BRIGHT ORANGE car!!

Parked right by the door in a handicapped space!!

Yet I remember the house phone number from when I was a little kid. And that was back when there were "word" exchanges rather than all numbers. Our area had EXpress, ENdicott, GArfield and many more.