for common THK in flat or disk mat sinnet,
I like those spirograph shape, that is to say, moving a little circle inside a big fixed circle, and any point in the little circle forms a curve, like THK.
every spirograph is a common THK, if you mark those crossings with the over-under pattern.
or should I say, every common THK is a spirograph.
like the Law of the Common Divisor,
the simplest fraction form of the radius (tooth) ratio of these two circles is THK leads and bights.
for example, try it online here
https://nathanfriend.io/inspiral-web/with typically out fixed circle 105 tooth,
and inner circle 63, ratio is 3:5 (21*3=63, 21*5=105), and then you get a spirograph of THK 3x5
if inner circle is 84, then ratio is 4:5, and then you get a spirograph of THK 4x5
if inner circle is 75, then ratio is 5:7(15*5=75, 15*7=105), and then you get a spirograph of THK 5x7
63 : 105 --> 3 x 5
84 : 105 --> 4 x 5
30 : 105 --> 2 x 7
45 : 105 --> 3 x 7
60 : 105 --> 4 x 7
75 : 105 --> 5 x 7
40 : 105 --> 8 x 21
50 : 105 --> 10 x 21
60 : 105 --> 12 x 21
80 : 105 --> 16 x 21
24 : 105 --> 16 x 35
36 : 105 --> 16 x 35
48 : 105 --> 16 x 35
72 : 105 --> 16 x 35
32 : 105 --> 32 x 105
52 : 105 --> 52 x 105
64 : 105 --> 64 x 105
and for out circle with 96 teeth:
24 : 96, --> 1L x 4B square
30 : 96, --> 5L x 16B
32 : 96, --> 1L x 3B triangle
36 : 96, --> 3L x 8B
40 : 96, --> 5L x 12B
45 : 96, --> 15L x 32B
48 : 96, --> 1L x 2B ellipse
50 : 96, --> 25L x 48B
52 : 96, --> 13L x 24B
60 : 96, --> 5L x 8B
63 : 96, --> 21L x 32B
64 : 96, --> 2L x 3B
72 : 96, --> 3L x 4B
75 : 96, --> 25L x 32B
80 : 96, --> 5L x 6B
84 : 96, --> 7L x 8B