Hello! So, for Christmas I've been designing a custom hand crossbow for my father using 3D printing. I have a 200lb rated trigger mechanism and a sturdy steel reinforced body. I'm using carbon fiber tubing as the bow limbs as well. So, most of it is designed but I still need to design the cam to make it a compound bow. I've tried making a similar mechanism to a compound bow but I used a pair of pulleys rather than a cam. I've been attempting research but I'm still not quite fully informed on how the shape of the cam affects the draw and strength of the bow. Some cams use an oval shape while others use a shape reminiscent of a Fibonacci spiral. In addition, how is the string strung around to make it act sort of like a gear multiplier?

Apologies if this question is too specific or dumb.