Try to encircle the cat with dark green dots without letting it get out.
Just click on a light green dot to make it dark green. The cat will move. Continue to click on light green dots to turn them dark green until you either trap the cat (encircle with dark green dots so the cat can't move) or the cat exits the dots.
If you fail to trap the cat, click reset to start the game over.
YES, it can be done...but you've got to outsmart the very smart cat.