-Try to make the circle the same color as the background by adjusting the amounts of red, green and blue light.
-Type numbers in the textboxes or slide the sliders to change the values. You can also use the up/down arrow keys when the sliders are selected.
-The magnifying glass shows what the screen pixels look like: try looking at them with a real magnifying lens!
-When you have a guess, click 'Show Answer' to see how well you did.