Is there a spell called circular light? Can you teach?

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I experienced a round light when I was a child! I am Tujia, and my home is in the mountainous area. There is a thing called "shadow egg" in our countryside. I was particularly uncomfortable when I was a child, and I had mental problems for a while. During that time, my mother and I were at my grandmother's house, and my grandmother later treated me with this "shadow egg" thing. She let me lie prone on the water tank, with my head facing the water, and let my reflection appear in the water. Then scoop out the reflected water with a water ladle (this is similar to a monkey fishing for the moon). Then boil the eggs with this water. ? Then there is the most incredible place. Grandma peeled the egg and there was a smile-like mark on it! About three strokes, two lines in the eyes and one line in the mouth. It was peeled off directly, not printed on the nails later. ? I don't know how it worked later, but this is really impressive anyway. Later, when I was in high school, I asked some classmates, most of whom had eaten, and I didn't know what was going on. This should be a round light, right? I am a good young man who loves science, but it is really incredible.