Algodoo

Lens maker uses Van Shooten's Hyperbola linkage to cut lens. Lenses made with a hyperbolic surface have sharper focus (less spherical abberation) than spherical lenses. Lens is attached to background with 2 axles. Delete axles, rotate lens 180 degrees, and connect to background to cut opposite surface. Copy and paste the finished lens into a drawing, change material to glass, and use. Hyperbolic and spherical lenses are shown below the mechanism to show the difference in focusing ability. Lens can be scaled to change diameter or focal point. Focal point can also be change by changing the refractive index of the glass.