# "Birds in the Forrest" Game

#### OCLawGirl

• 503
##### "Birds in the Forrest" Game
« on: September 28, 2006, 10:00:42 AM »
1.  "If wrens are in the forrest, then so are grosbecks."  Can the diagram be represented as either:

W-->G or G-->W

2.  "If Harriers are in the forrest, then grosbecks are not".  Can the diagram be represented as either

H<--I-->G or G<--I-->H  (I represents not symbol. ie, line going throught he double sided arrow)

Thanks!

#### umass22

• 893
##### Re: "Birds in the Forrest" Game
« Reply #1 on: September 28, 2006, 10:12:56 AM »
can you also infer that W-->H?

#### OCLawGirl

• 503
##### Re: "Birds in the Forrest" Game
« Reply #2 on: September 28, 2006, 10:16:22 AM »
That's what I thought. (G-->W no) But on the explanation in the LGB, it states:

"J<--I-->W  This inference results from linking the 1st inference J<--I-->G and the 3rd rule W-->G."  How can combining J<--I-->G and W-->G result in J<--I--W?

I understand getting J<--I-->W by combining J<--I-->G and G-->W (ie J<--I-->G-->W)

What am I missing?

#### umass22

• 893
##### Re: "Birds in the Forrest" Game
« Reply #3 on: September 28, 2006, 10:16:54 AM »
can you also infer that W-->H?

W ---> G ----> H
haha, yeah i just noticed that I had that backwards with the H and was about to change it.

#### OCLawGirl

• 503
##### Re: "Birds in the Forrest" Game
« Reply #4 on: September 28, 2006, 10:27:15 AM »
That's what I thought. (G-->W no) But on the explanation in the LGB, it states:

"J<--I-->W  This inference results from linking the 1st inference J<--I-->G and the 3rd rule W-->G."  How can combining J<--I-->G and W-->G result in J<--I--W?

I understand getting J<--I-->W by combining J<--I-->G and G-->W (ie J<--I-->G-->W)

What am I missing?

easy.... W ---> G and G ---> I---> J, then W ---> G---> I---> J

i find it easier to diagram in single groups, that is:
W ---> G
W ---> I
W ---> J

Aaah...so you are going backwards:  W-->G<--I-->J becomes J<--I-->W.
Does this mean J<--I-->G and G<--I-->J are the same thing?

#### LizPendens™

• 4467
• The Real Alice -- Adventures in Wonderland
##### Re: "Birds in the Forrest" Game
« Reply #5 on: September 28, 2006, 10:39:20 AM »
No rule 1 cannont be as you have it.

W--->G  yes

G--->W  no

Grosbecks can be there without wrens, but wrens cannot be there without grosbecks.

and the second one i would do as follows

H ----> G

again, this does not mean G ---> H because neither HAS to be in the forest.

alright, i'm looking at the problem now and these are the diagrams i made:

From rule 1.

H ---> G

From rule 2.

M ---> H
J ---> H

From rule 3.

W ---> G

From rule 4.

J ---> S

Combining all the rules for W i come up with this:

W ---> G
W ---> H
W ---> J
W ---> M
W ---> S (because J can't be there)

also:

J ---> G
M ---> G (because J or M ----> H ---> G)

trapping for posterity and to save from being laid waste from the vile scourge, d-dubbing.

#### OCLawGirl

• 503
##### Re: "Birds in the Forrest" Game
« Reply #6 on: September 28, 2006, 11:00:20 AM »
Does this mean J<--I-->G and G<--I-->J are the same thing?

#### LizPendens™

• 4467
• The Real Alice -- Adventures in Wonderland
##### Re: "Birds in the Forrest" Game
« Reply #7 on: September 28, 2006, 11:05:01 AM »
Does this mean J<--I-->G and G<--I-->J are the same thing?

if you are saying that

if J is in the forest, G is not
and if G is in the forest, J is not then yes.

BUT...they could both be out of the forest.

gotcha.

#### OCLawGirl

• 503
##### Re: "Birds in the Forrest" Game
« Reply #8 on: September 28, 2006, 11:07:37 AM »
Aaaah!  That makes sense!  Thanks!

#### n/a

• 1826
##### Re: "Birds in the Forrest" Game
« Reply #9 on: September 28, 2006, 12:32:54 PM »
I remember setting up one giant if-then chain and kicking the crap out of this game in about 5 minutes.  Im not very good at games overall though, so Im kind of surprised to see everyone else found it so difficult.