LOW STRINGS---  ---HIGH STRINGS
                 6  5  4  3  2  1 ---string number
   fret # -  O   E  A  D  G  B  E ---name
                 ================ ---nut
             1   |  |  |  |  C--+----True piano
                 +--+--+--+--+--+    "Middle C"
             2   |  |  |  |  |  |    (piano notation)
                 +--+--+--+--+--+
 Guitar------3---+--C  |  |  |  |
"Middle C"       +--+--+--+--+--+
 (guitar     4   |  |  |  |  |  |
 notation)       +--+--+--+--+--+
             5   |  |  |  |  |  A----"A-44O"
             |   +--+--+--+--+--+    (tuning fork)
            \|/  |  |  |  |  |  |
            etc.