... speaking of St. Andrew, this is from Wiki:
A saltire, Saint Andrew's Cross, or crux decussata (though it is never called the last in heraldry), is a heraldic symbol in the form of a diagonal cross or letter X. Legend relates it to a diagonal cross that Saint Andrew is said to have been martyred on.
Oh dear ... it is also used in "BDSM," or so the picture on Wiki clearly illustrates (okay,
semi-clearly).
I guess I knew, but never - umm, wait,
nevermind.
Around here, we see it on license plates on the
front of cars a lot, as the Flag of Scotland.