I'm trying to understand the wave behavior of light and have questions on diagrams of it. Wiki shows the following two diagrams from Christian Huygens describing the wave nature of light. I have seen similar diagrams elsewhere. How do the black curved lines in these diagrams relate to the third, showing an electro magnetic wave? Are the peaks of $\vec E$ in red equivalent to the curved black lines? Also, do the black lines represent peaks on one side of the surface wave in the fourth picture?