Notice that there are actually ONLY twelve different tones on the keyboard within one octave.

This means that amongst all the seemingly confusing and confounding Western music theory
notation and analysis, we are really just talking about arrangements of these twelve tones.

It may also be helpful to think of these tones as twelve equal blocks.
Tinker Toy Blocks.
Tonal Tinker Toy Blocks.
Remeber that really funky song on Sesame Street where they just count to twelve over and over?
(see figure 3)

The tonal space between notes is occupied by what are called semi-tones.

The Indian Classical music tradition is one among many that make full use of semi-tones and are
not based on a twelve tone system. Our discussion will focus primarily on the twelve tone system.

1 2 3 4 5 6 7 8 9 10 11 12
C
D♭
C♯
D
E♭
D♯
E
F
G♭
F♯
G
A♭
G♯
A
B♭
A♯
B