Animation 4. Spreading of reradiation from free electrons. This is similar to the bounded electron case except that the reradiation (red waves and phase lines) is 180 degrees (i.e. exactly opposite) to the initial EM field (indicated by the blue waves and phase lines). As with the earlier bounded electron example, the initial radiation is from a distant source, and therefore the phase lines are virtually straight and parallel. The reradiation spreads out from the electron, and therefore the phase lines are curved.