Minor Seventh Chords
--------------------
The formula for minor seventh chords is 1, b3, 5 and b7.

, C form        , A form               , E form        , D form
+-+-+-+-+-+     +-+-+-+-+-+          +-+-+-+-+-+     +-+-+-+-+-+
| | | | 1 1 -11 1 1 1 1 1 1 -3       1 1 1 1 1 1 -8  | | 1 | | | -10
+-+-+-+-+-+     +-+-+-+-+-+          +-+-+-+-+-+     +-+-+-+-+-+
| | | 2 | |     | | | | 2 |          | | | | | |     | | | | 2 3
+-+-+-+-+-+     +-+-+-+-+-+          +-+-+-+-+-+     +-+-+-+-+-+
| | 3 | | |     | | 3 | | |          | 3 | | | |     | | | 4 | |
+-+-+-+-+-+     +-+-+-+-+-+          +-+-+-+-+-+     +-+-+-+-+-+
| | | | | |     | | | | | |          | | | | | |     | | | | | |
+-+-+-+-+-+     +-+-+-+-+-+          +-+-+-+-+-+     +-+-+-+-+-+
| 4 | | | |     ===========          ===========     =========== 
+-+-+-+-+-+     5   5   3b           1   7b  5       x   1   7b  
===========       1   7b  5            5   3b  1       x   5   3b
x   3b  7b  
  1   5   3b  
   
I omitted the G form, as it's practically unplayable.  The C
form is fairly difficult as well.