Setup and Rule Diagrams

[Dave Killoran]

Setup and Rule Diagram Explanation

This is a Mapping—Spatial Relations game.

A superficial reading of this game suggests that it is a Mapping—Spatial Relations game. The five islands are connected by bridges, and the entire scenario and rule set has the feel of a game that must be drawn out. However, a key consideration is missing from the rules: none of the bridges has to be straight. This fact completely changes this game, and makes virtually any configuration of bridges possible. Thus, the game turns from a Mapping game and becomes a Grouping game, where the connection possibilities are paramount. Remember: in games that appear to be based on mapping or connections, always determine whether the connections must be straight or not. If they are, then the game is about drawing; if they are not, the game is about grouping.

With the straightness of the bridges a non-factor, we can ignore the rule about intersecting bridges and focus on the connections between the islands. In fact, in our diagram we won’t be concerned with any intersections—we just will focus on the connections.

Initially, we know there are five islands: J K L M O5.

The fourth rule divides the islands into two groups: J, K, and L, which are each connected to M or O or both. Thus, our initial diagram will show those islands in two separate columns:

PT6-Oct 1992 LG Explanations game 4 setup diagram 1.png

Of course, the last rule establishes that J is connected to O, and O is connected to M:

PT6-Oct 1992 LG Explanations game 4 setup diagram 2.png

Note that the connections have no direction, so there are no arrows at the end of each line. This means that once an island is connected to another, the connection goes “both” ways.

Note that O now has two connections, and from the third rule we can infer that O can connect to at most one more island. Because K and L must connect to M or O (or both), we can infer that if K connects to O, then L must connect to M. Alternatively, if L connects to O, then K must connect to M. These two inferences can be shown as:

PT6-Oct 1992 LG Explanations game 4 setup diagram 3.png

The parentheses are not necessary, but they are used here for the sake of clarity.

The last point of analysis is to analyze the fifth and sixth rules. The sixth rules states that K is connected to exactly one other island. From the third rule, we know that island must be O or M:


                         K O/M


The fifth rule states that J is connected to exactly two islands. From the seventh rule we already know that J is connected to O, so O must be one of the two islands. The other three choices are K, L, and M, but because K can only connect to O or M, J cannot connect to K, leaving J with the choice of one of L or M (J cannot connect to both L and M because that would connect J to three island—O, L, M—a violation of the fifth rule). Thus, J connects to O and either L or M:


                         J O, L/M


With this information, we arrive at the final setup to the game:

PT6-Oct 1992 LG Explanations game 4 setup diagram 4.png

[Jkjones3789]

Hello, I am a little confused as to how to the deduction that neither JK or KL can be connected could you please clarify this for me? Thanks

[Jon Denning]

Hey Jk,

Thanks for the question! Let me see if I can help you out.

This is a somewhat tricky Mapping game, and you've noted a critical two-part inference. We're told from the rules that (1) J, K, and L are each connected to either M or O, and (2) K only has one connection. What that means is that K's single connection must be to either M or O, and cannot be to anything else (so no JK or KL).

I hope that helps!

Jon

[mattm]

Hello,

I was wondering, what would be your take on how to set up and approach a Game like the last game in the set? I was somewhat confused by the openess of the game in that any of the islands could have been placed anywhere it seemed as long as the rules were followed?...

It seemed very free as we don't even know the configuration ( circle, rectangle etc) as the LSAT often gives some basic framework

I would like advice on this game in particular but would also be interested as in a broad picture how should i attack a similar game on Test Day?

Why in your opinion has the LSAT stayed away from these types of games in recent memory as the spatial dimensions/distances have been not tested much at all, but have focused on other things such as sequencing or grouping type of games?.....I still want to use old games as practice in case a situation like Feb/June 2014 shows up on my exam ( LG is a strong area for me so I can use time on rare games), ... my feeling is although Sept/Dec 2014 only featured more standard games, it is likely so LSAC can use them to keep unprepared test takers off balance ( if Sept/dec 2014 featured unusual games as well, it would be very obvious rare games would be on the test, so it is in the best interests of LSAC to be unpredictable and have some exams where all four are standard games)

Thanks!

[Dave Killoran]

Hi Matt,

This game is actually an awesome one to teach you what is important in a game and what to look for. Most people, upon encountering this game, try to turn it into a diagramming exercise, and you see them drawing out islands and bridges, trying to make it so the bridges don't intersect, etc. However, you noted that it was really open, and that's actually a tipoff: this isn't a Mapping game, but a Grouping game. The way you know this is that they never say the bridges are straight--they can curve and bend around, and so there are a million different configurations. They can't test that many options, so you have to focus instead on the relationships: which islands can and cannot be connected to each other. With that in mind, I just set up J, K, L, M, O in a straight base, and then put the islands each connects to above, and eliminate any islands they can't connect to by marking them out underneath. From that angle, it becomes a grouping game, and WAY easier

What's LSAC up to recently by having fewer odd games? Nothing unusual, actually. They have a long history of using some games types heavily at times and then having them disappear entirely for a while. Circular games are great example of this, and think about how effective that tactic is: if a game type hasn't appeared in a decade, then no one is really well-prepared for it so when they do throw it in, it blows a number of people away. If they had that game type on the LSAT frequently, everyone would be better prepared and the game would be less effective as a separator. This is why we always try to cover the "rare" stuff because most of it comes back at some point.

Please let me know if that helps. Thanks!

[nishtha28]

hello,
I am still very confused on how to diagram this game or start it can you please explain how you wrote variables down for the islands? or how you deduced the bridges to the island?

Thanks

[Christen Hammock]

Hi Nishtha!

Don't get too caught up in getting the diagram "right" from a creative standpoint. This is just a grouping game, as Jon and Dave mentioned above! This is what it looks like to set up the base variables:

___ ___ ___ ___ ___
J   K   L   M   O

From there, you can treat this game like any other grouping game! For example, Rules 3 and 4 can be diagrammed as follows (using J as an example):

_____
M/O
J

In other words, we know that J can only be connected to two other islands, and one of those spaces must be filled up with either M or O. There's no need to draw pictures or make a complicated map! We're just pairing variables together.

Christen