Paint What You See
Around 1948 or ‘49, laying on my back on our lawn in South Gate, looking straight up into a flawless blue sky, I enjoyed watching undulating patterns which filled my vision. The longer I looked at them, the more they activated, faster, and crazily more complicated. Looking higher, the surface of the patterns filled the space between distant blue and me on the ground. It felt like I was reversed, I was falling into the deep sky.
Somewhat later, maybe ’52 or 3, a neighbor friend my age taught me to grab tight my folded legs as I sat on the grass, pulling my knees to my chest, forcing panting breaths until I collapsed unconscious on my back. As I regained consciousness, my vision was filled with flashing intricate patterns like 3D wire forms containing kaleidoscopic stained glass colors. The powerful show slowed, dimmed, gone in a minute.
Cosmologists refer to a "surface of last scattering" when the photons last hit matter; after that, the universe was too big.
At some point, photons ceased to scatter at all and began to propagate freely through the Universe. These photons reach present-day observers as the cosmic microwave background radiation. This radiation appears to come from a spherical surface around the observer. This surface is what is called the last scattering surface or "The Surface of the Last Scattering.”