A nice way to think about swords is that they move kind of like fegundoes, except they don't blow up if they hit an obstacle; it's more like they just wait in place (like a fegundo hitting a force arrow or an orthosquare).
So, you'll need a path that doesn't have too many sharp turns in it.
Since you only have vertical tunnels, and not horizontal tunnels, this also implies your path should be mostly vertical - you don't have much time to make many horizontal moves.
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×You'll want the sword to face South, and make a southeast move into the stalwart.
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×To do that, you can use the tunnels to make the sword turn around...
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×if it's currently at (17, 13) and would get blocked by the western obstacles as it turns around.
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Quick links to my stuff (in case you forgot where it was):
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