Q9

[CourtneyH949]

What is an efficient way to solve this question? I started by creating a new diagram with the new condition, but I was unable to make many inferences from it. Is there a better way to solve this than trial and error?

[Laura Damone]

Hi!

In my big pause, I thought about framing around the T __ __ W open chunk. It can only go in 2/5, 3/6, or 4/7.

I decided not to go for it because each frame would still leave 2 options for the placement of the UX reversible chunk, but I kept it in mind as I played the rest of the game.

When Q9 placed Z in 7 but didn't start a domino effect of inferences, I deployed some question specific frames. Since slot 7 is full, only the 2/5 and 3/6 options for the TW chunk remained, giving me:

___ ___ T ___ ___ W Z

___ T ___ ___ W ___ Z


In the bottom frame, we must place the UX chunk between T and W, with X in 3 and U in 4 to avoid violating the WX antichunk. That leaves S and R for 1 and 6. Since S are also an antichunk, we get:

S T X U W R Z

In the top frame, the UX chunk could go in 1/2 or in 4/5. Wherever UX doesn't go, S and R will. That's hard to type out, but on my scratch paper I have "UX/RS" over slots 1 and 2, with a little "suitcase handle" over UX and another over RS to indicate that their order isn't fixed. I have the same thing, inverted, over slots 4 and 5.

With these frames, I can mow through A-C. D looks possible, and at first E does, too. But upon closer consideration, E doesn't work because placing X in slot 5 in the top frame places it next to W, which is illegal. So, if UX chunk goes in 4/5, the order is determined: X4 U5.

Question specific framing is a great strategy when the new rule in a question doesn't start a cascade of inferences. If it's not something you regularly do, start looking for untapped opportunities in old games and make it a standard tool in your toolbelt moving forward!

Hope this helps!