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SPEAKER 1: All right, let's
have a look at non-threatening.

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So non-threatening we
are given a chessboard

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with a bunch of letters on it
and several pieces already placed

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on the board, one queen
and the eight ponds.

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And we have these seven pieces
remaining indicated at the bottom there.

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And apparently our goal is to find a
way to safely place all of the pieces,

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so that none of them are
quote, unquote threatened,

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which means basically they're
subject to attack by that piece based

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on the rules of chess.

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Now of course, all the
pieces in this are white.

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There's not actually two
opponents going on, so

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think of this more of like a civil
war where the pieces are possibly

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going to be able to attack each
other even though they're all

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on the same side.

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So the first thing that you might want
to do in this puzzle is figure out

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where pieces cannot possibly go based
on the chess pieces that are already

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placed on the board.

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Because by placing them
in any of those spaces,

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they would already be threatened or
subject to attack by some other piece.

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So for example, Queens as you may know
are the most powerful piece in chess.

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They can move any number of
spaces in any direction, which

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means putting pieces
in any of these squares

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would immediately put them under
threat, because the queen could

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move to any of those squares freely and
could attack any piece in any of them.

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So we can rule all of those out.

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Additionally, pawns, the pawns can
only generally move forward in chess.

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They attack diagonally
forward, which is, kind of,

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a strange quirk of that piece.

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And so we can also eliminate any of
the two squares, or some of these pawns

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are right on the edge of the board so
we might not be able to eliminate them.

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But any of the two squares
diagonally in front

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of any of the pawns, which means we
can also eliminate any of these squares

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as well.

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So we know right out the
gate that we can't possibly

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put pieces in any of those spaces.

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So where to go from here.

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Well, this is really going to be a
game of trial and error and logic.

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And there are so many ways
to approach solving this

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that we're actually just
going to, kind of, generally

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go over some strategies
to approach this,

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and then we'll just kind
of hone in on the answer.

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So for example, the easiest
ones to probably figure out

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are the rooks, which are
these two pieces here.

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Rooks, as you may know, can
attack similar to the queen,

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but they can't go diagonally.

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So they can move up and down or left
and right any number of positions.

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Now if we look at the rows and
columns on the board that currently

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have no other piece in them, that
really only leaves four possible spots

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for these rooks to go.

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And really they actually have to
exist in either of these pairs,

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either the t and the
s or the w and the e.

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Because, otherwise, then if we put them
in the same column or the same row,

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they could attack each other,
which would make them no longer--

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they'd be threatened.

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So they wouldn't be non-threatened.

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So we know that the
rook's have to go there

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for sure in one-- in some
of those squares, which

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allows us to actually
eliminate all of these squares

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as well as possible locations.

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Because regardless, there's going to
be one rook in one of those columns,

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one rook in the other, and similarly
one room in one of those rows,

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one rook in the other.

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So that omits all of those
other squares as well.

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From here you just, kind of, need to
figure out where other pieces could go.

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So for example, if we take
a look at the bishops here,

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bishops are like rook's except
they only attack diagonally.

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So they can go as many pieces as
they want, but only along a diagonal.

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And if you take a look at
what's left on the board,

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these are the only places
that rook's could go.

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The night's attack in an L-shape.

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I don't have them on the
slides here, but similarly you

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could figure out where
they could possibly

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go to not end up in a red square
and not capture some other piece.

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And the king is similar to
the queen, except it can only

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go one square around where it is,
but can attack in any direction.

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So based on that information,
applying some logic and some practice

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and just guessing, you can figure out
that ultimately the pieces that-- well,

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the places where we want
to put the pieces are here.

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And if we do that now, all
16 pieces from the white side

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are not threatening each other.

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And if we look at the letters
that are underneath those squares

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and read those again from left to right,
top to bottom, we get the word welcome.

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And that was the answer
to non-threatening.