Two beams

Persoa autora:
Patrick Ion
The beam about A rotates at signed variable 'a' times the uniform speed that the beam at B rotates; the 'gamma' variable is the animated phase at B. The beam at B is displaced in initial phase by variable 'delta' from the right horizontal where 'gamma' starts; 'gamma' oscillates between just under -2pi and over 2pi. F is the intersection point that leaves a trace of positions it has been.