#2228: Machine Learning Captcha explain

[Cueball is sitting in an office chair at his desk with one hand in his lap and the other poised over the keyboard of his computer. A zigzag line is drawn from a starburst on the computer screen going above the computer to where it is shown what is displayed on the screen. At the top there is the following text:]

Computer: To prove you’re a human, click on all the photos that show places you would run for shelter during a robot uprising.

[Below the text there are nine images arranged in a 3 by 3 square. In reading order they are: A house, possibly with an open carport; a large tree with two trees in the background; a bunker/bomb shelter; a car; a city skyline with several sky scrapers; a sidewalk with road on the left, grass on the right; a log with a board leaning up on the log; a mailbox; and a hole in the ground.]