LSAT 62 Stained Glass Windows Game 2: Setup Rule 4 Pitfall! Part II

LSAT 62 Stained Glass Windows Game 2: Setup Rule 4 Pitfall! Part II

At first glance, it might appear that P & O are mutually exclusive. However, let’s consider the rule and its contrapositive. What it is actually saying is:

In the absence of P, O appears.

In the absence of O, P appears.

In other words – one of the two always has to appear. Either O, or P.
This is a pretty helpful deduction, in fact. It means we can place one of these in windows 2 & 3: an O/P. Why? Because we always have to have an O or a P.

LSATwin 62 Stained Glass Windows Game 2 Setup Rule 4 Part II LSAT 62 Stained Glass Windows Game 2: Setup Rule 4 Pitfall! Part II

LSATwin.net 62 Stained Glass Windows Game 2 Setup Rule 4 Part II

Why don’t we place it in window 1? Because window 1 already has a P.
Notice that that doesn’t bar O from showing, as well.

This is the key realization to avoid falling into the false deduction pitfall:

O & P can still show together.


Note that neither the rule, nor its contrapositive, apply if O and P both show – because the rules are only triggered when O and/or P don’t show.

In other words – O & P both appearing is fine.
It is a common, and false, deduction to read these rules as O and P don’t appear together – and you’ll pay the price on the questions following.

So there we have it.  A master diagram that tells you – better yet, shows you, the boundaries of all the agents. Ideally drawn, you never go back to the text. Reading is slow, and will prevent you from finishing the games. Visual information is fast – and that’s why you took the time to draw it out. Besides, mapping the game helps you understand the structure and logic of the particular game. As you can tell, in comparison to the previous game, every game is different and requires you to formulate your master diagram around the information contained herein.