CHARLIE
          Imagine a rainbow...

AUDIENCE VISION:
Charlie suddenly steps outside into a bucolic scene -- a
massive rainbow behind him in the sky.

                    CHARLIE (V.O.) (cont'd)
          -- which is formed when a beam of
          white light...
          
We MOVE into a beam of white light that moves through drops
of rainwater.

                    CHARLIE (V.O.) (cont'd)
          ...passes through drops of 
          rainwater in the air and is
          refracted or bent.

Rainbow formation on a disk-like raindrop. Drag the locator up and down to vary where the light ray strikes the raindrop, or right and left to thicken the ray lines.

                    ALAN
          Sorry I'm late. Got the scouting 
          report on our opponent -- good news 
          is they're the worst team in their 
          conference. Bad news is, compared 
          to us they're great. 
            (then) 
          What are you doing anyway?

                    CHARLIE
          Gaussian filtering.

This Demonstration shows the smoothing of an image using a 2D convolution with a Gaussian kernel. The kernel is sampled and normalized using the 2D Gaussian function.

Don and Robin look at a computer, which shows Charlie's
results.

                    DON
          So what are we looking at here?

                    CHARLIE (V.O.)
          Those wavy lines...

Chladni figures are wavy lines produced by scattered salt or sand on an elastic material of a given shape, possibly constrained at the edges or at a point in the center, and forced to vibrate with a violin bow. The modes of vibration can be identified because these small particles end up in the places of zero vibration, which happens at those parts of the surface that are stationary, namely at the nodes of vibration, where n harmonics cancel.