http://www.dothetest.co.uk/
Take the test...see how you do.
I failed
Sorry if you've seen it before
I failed.
It is startling and it illustrates that we see what we expect to see. Vision is an active process, not a passive one.
I was a passenger in my sister's car once as she approached a T intersection. She had to stop but crossing traffic did not. "Watch for that bike" I said as a cyclist came from the left.
"What bike?" she asked as she pulled out in front of him.
He did a panic stop and turned the air blue with profanity. I know exactly how he felt.