This (silent) video captures a screencast of Optopus varying the curve of the ingress face of a diffuse lens while tracing rays from the 0, 10, 20, 30 and 40-degree incident sub-beams to their respective foci. The Optopus script for this is quite simple and mainly comprises setting up the display. The lens is morphed from a long to short focal length by a single fade command. A complementary fade command returns it to the long focal length. The flickering in this video is an artifact of the screencast capture program.

SCRIPT

window -1,-1,800,635,INRB,4,4
canvass 1000,700
width 48
lens 516,669,292,365,119,CVCC 
pause
delay 500
loop
fade 516,669,292,365,119,CVCC  516,223,292,365,119,CVCC  20
fade 516,223,292,365,119,CVCC  516,669,292,365,119,CVCC  20
endloop