While I was in Austin, at Veritas Academy, we went through a discussion speculating about the signs used in addition (+ adds a vertical line to -, – subtracts the vertical line from +, = are two equal lines). It was pretty exciting for me, because it indicated that the signs actually do mean something.
You can imagine the thrill I felt when I opened my History of Mathematics by Carl Boyer, opened it rather randomly, and read these marvelous confirming words by Robert Recorde (who, as we all know, made the two equal parallel lines the “equals” sign):
I will sette as I doe often in woorke use, a paire of paralleles, or Gemowe [twin] lines of one lengthe, thus: =, bicause noe 2. thynges, can be moare equalle.
Not much for spelling and grammar ; ), but what a great historical discovery this is, at least for me who loves these cheap thrills that connections and detections give me.