Computation times

00:21.408 total execution time for 7 files from examples/04-lights:

Example	Time	Mem (MB)
Shadows (shadows.py)	00:07.784	0.0
Plotter Lighting Systems (plotter_builtins.py)	00:07.243	0.0
Light Types (light_types.py)	00:02.127	0.0
Light Actors (actors.py)	00:01.434	0.0
Beam Shape (beam_shape.py)	00:01.349	0.0
Disabling Mesh Lighting (mesh_lighting.py)	00:00.803	0.0
Attenuation (attenuation.py)	00:00.668	0.0