Click on one of the squares on his chest to find the puzzle. Oops, puzzles -- one for each head, I guess. Read to the end for one way to do this.
Hint 2
What you're doing here is clicking on the paths between the white circles to block them. When you've blocked all possible paths, you win.
Hint 3
The trouble is the dog is moving at the same time, so you have to plan ahead. (Though I should point out that he doesn't always move the same way, so you need to stay alert.)
Hint 4
The first block you place should be to protect the star the dog is likely to reach first.
Hint 5
Once that's safe, wait and see where he moves next. Remember that there are many routes to each star, and you have to block them all.
Hint 6
In some cases, your best move is to block the routes directly into the stars. In other cases, it's better to block the routes leading to the routes to the stars.
Hint 7
Be prepared to play over and over as you discover the dog's routes.
Hint 8
The way the dogs move is fairly consistent, but they don't make exactly the same move every time. Even if you use my moves, you may suddenly find a dog making a direct threat against one of your stars. If that happens, abandon my moves and make your own moves.
Hint 9
Any way you do this is the right one, but here's what worked for me (most of the time):
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