Resize your browser window to find the black circle.
It will only appear when both dimensions of the browser window are correct.
The width and height numbers will turn green as you get closer to the correct size.
When one of the dimensions is correct, a blue checkmark will appear next to the number.
Once the width and height of the window are correct, click on the black circle that appears.
You start with 60 seconds. Each spot you click adds 5 seconds to your time.
Try to spot as many spots as you can!