Algodoo

nice!
If you want, you can have a look at my aspheric lense, which has
(for the specified color)
a real focus, i.e. all laserbeams cross at the SAME point, which is called F, Focus.
it is scene 72210.
Even better is the work of noonan: scene 43943
you can find both , if you search the algobox with for the word "aspheric"

@noonan: how did you make your aspheric lens?