This page is work in progress.

 

Starting from the mid-left.

Up the scale C-D-E-F-G-A-B, move over to the right. Down the scale  B-A-G-F-E-D-C. Down again an octave lower B-A-G-F-E-D-C. Move to the right and up   C-D-E-F-G-A-B.

 

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The symbol for the difference between two entities. 

E.g. –  the difference between A and B is (symbol) 1.