This simulates light reflecting on a shiny metal surface. The red wave is the incoming wave
This wave will cause the electrons in the metal to move until the induced field reach the same
strength as the incoming field. This will cause an outgoing wave with a phase shift of
close to 180 degrees. The induced field will propagate both to the right and to the left
and the field to moving to the right will interfere destructively with the incoming wave.
The result will be that no light will move through the metall. In the opposite direction
the two waves will create a standing wave.
The blue dot reprecent the electrons, and the arrows the respective electric fields.
The gray curve reprecent the sum of the incoming and induced fields.
Observe that this is a simulation, not just drawn curves. One can see that at the
start where one can see that it takes a while for the electrons to move through
simple harmonic motion.