The letters are converted to notes by Modulo 7, which the letters take the letters A-G once every 7 letters.
e.g.
A → A, B → B, .... , G → G
H → A, I → B, .... , N → G
O → A, P → B, .... , U → G
In this case the motif is translated into E, B, D, D, G, E, B, C
Then the motif was added with dotted rhythms
The second theme is based of Bach's motif (B - A - C - B♭) and one of the section in a Bach fugue
The fugue switches between Aeolian mode and the conventional mode