a man standing up right with a women place directly infant of him with her hair the angle from the camera makes it look like this is the man beard but it is actually just the women's : High cognitive effort.
One of my favorite things that was shown to me during my elementary age years was an optical illusion. It was the very famous Rubin Vase (pictured below) which you can see in either two ways - as a vase or as two faces that are facing each other.
This handout summarises all the key programming concepts in the Python 3 programming language. It is useful for students who are learning to code, or to have on hand when they are revising their skills.