Here are two other examples of how to see the mind alter what you see while you are actually looking at something. This is what they call an illusion (an instance of a wrong or misinterpreted perception of a sensory experience).
The following experiments may take a long time before actually witnessing the effect. But I assure you it is worth it, for you will realize that what we may be seeing is not necessarily so. It may shock you to find that what you see is actually not from your eyes, but from your own mind.
I like introspection to find deeper truths about myself. This requires sitting with a single thought, such as a single word, and staying with that word for at least 30 minutes. It is not easy to do, because the mind will try very hard to get you to think of other things. The ego-mind will get threatened after a while because of you not paying attention to it. It will even try and convince you that it is insane to carry on with the experiment. To carry on becomes an act of faith.
For me, after about twenty minutes of mental gymnastics, the mind quietens down. After a while, in that quietness, something else arises to mind, as if to say "Is this what you are looking for"? Quite often it becomes a revelation.
One day, I was looking at a newspaper headline. The first letter was 'B' and I decided to focus on that letter for as long as it took to see what truths I could gain from it. After about twenty minutes the letter 'B' changed its appearance to look like 'P'. I ignored it and still staring at this 'P' for another five minutes and then it change to look like 'b'. Then I snapped out of my focussing in awe about how the mind works to please us. In each case, the mind was looking for a solution to my enquiry into the letter 'B'.
Another experiment is to look at a face. Same thing happens as explained above, but what happens is that the face changes appearance. The original face has a left and right side. In the changing of appearance, one side becomes the mirror of the other side, example: a left side and mirror left side. Then later you will get two right sides.
As I said, it is not easy to experience these illusions. It takes a fair bit of patience and single minded focusing, regardless of what the mind may say about yourself during the experiment. Don't worry, you won't go insane.
Actually, in psychology, we get taught to read both sides of a face. One side often expresses something different to the other side. Such as a smile with a touch of apprehension on the other, may possibly indicating a false smile to pacify someone. Try this out on photographs in newspapers. Find out what they were actually saying at the time of the photograph. Then cover one side of the face to read what it is saying to you, then cover the other side and read that. You might find that one side opposes to what they were actually saying, indicating a possible deception. Don't take any of this too seriously though, sometimes a face maybe about what they are going to say next, and not necessarily what they have said then. In other words, like all body language readings, it is
not necessarily so.