I think I saw something about this in another thread. It involved using a primitive box and pointing the light at it, and shrinking the box down to the smallest size you can. There might have been more to it than that, but that's all I remember.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi