When you've created the pits, own a few dogs and 2k in funds and your house withstands 2k suicide robbers, you have to actually let someone rob you.
You place the cats, but not dogs and the vault where your wife would be. In self test you see, if all the cats fall into pits. Protect your wife somewhere else this one time. After being robbed the pits are permanantly full of dead cats.
It is not possible to do this with cats and dogs alive, because the dogs will move simultaneously. Your example would look like this I guess: http://castledraft.com/editor/2cJjuw
]]>http://castledraft.com/editor/0TvHVh
Note that what you are trying to do is easier in the downward direction because of pet movement order.
Edit: Oops, second dog from the bottom should be one square up, fixed it now.
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