Theoretical base of the circle drawing algorithm is: http://www.mathopenref.com/coordcirclealgorithm.html
Chord calculation algorithm used by trapezoid shaped cogs: http://www.mathopenref.com/chord.html
Theoretical base of the circle drawing algorithm is: http://www.mathopenref.com/coordcirclealgorithm.html
Chord calculation algorithm used by trapezoid shaped cogs: http://www.mathopenref.com/chord.html