Drill 20 - erroneous or unclear

[NikitaB917]

I have a few questions regarding Drill 20 (p. 145). Either I'm missing something or there are a few errors here.

On number 23, P/V and S/T are listed as Twins—but why? If S is on a team then T is not on that team. There is no twinning to be had there. And if P is later than R there is no guarantee that V will be later than R.

On number 32, T/B and P/W are listed as Twins—but why? Since the rules do not overlap, it seems impossible to say anything about T and B or about P and W, which appear in different rules.

On number 35, H/L are listed as Twins—but why? As for number 23, if H has one flavor L has a different flavor. The more appropriate Twin match seems to be between M and K: for any given flavor, if M has it then so does K.

Am I missing something basic here? Or are these bonafide errors?

[Laura Damone]

Hi!

Sorry for the delayed response here. This one slipped through the cracks!

Ok, in 23, P and V are twins because they are each impacted by rule 3 and rule 3 only: R is always earlier than P or V. That means, when R is placed, you know that P or V must follow. And because they aren't impacted by any other rule, they're functionally interchangeable. If R was in the second-to-last slot, we'd put P/V in the last slot. Until there is some other rule introduced, where P can go V can go, and vica versa. That makes them twins.

S and T are in the opposite situation: Where one goes, the other does not. They are mutually exclusive and biconditional. But if you build out each of the two groups in this game, in one group you'd put S/T and in the other you'd put T/S. They aren't impacted by any other rule, so they, too, are functionally interchangeable. Even though they can't go together, they still bend to the same rules. That makes them twins.

For 32, though, I think you found an error, so thank you! I do, however, think you could rightly call C and S twins, as well as T and W, and B and P. Each of those pairs is part of a One in / One out rule and nothing else. So, for C and S, at least one of them must be out, but we don't know which. Could be just one, could be both. I'd represent that with a C/S placeholder in the out column. So in that sense, C and S are interchangeable. The TW and BP rules would each generate a placeholder in the In group: T/W and B/P. At least one of each pair must be in, and because they aren't impacted by any other rules, each pair is functionally interchangeable.

And for 35, you found one error, but not two . I agree that M and K should be listed as twins. They bend to the same rule in the same way. They should also be listed as game drivers, but that's another matter! But it's also true that H and L are twins. As in 23, they are mutually exclusive but functionally interchangeable. Into the diagram, I'd place H/L in Chocolate and L/H in Vanilla.

Thanks so much for looking at this so diligently! We'll make sure these errors don't make it into the next edition of the book. More broadly, there is some degree of subjectivity to considerations like Twinning and Game Driving. We've tried to make the book as objective as possible, but what one writer or editor sees as a twinning, another might not. Certainly the Twins listed in 35 were downright wrong. They should not have been listed. But my proposition for correct twinning relationships in that game is kind of "take it or leave it." Technically, I think they're twinning. But as long as you recognize the placeholders those rules generate, you're on track to beat the game and I don't really care whether you call them out as twins or not.

Hope this helps!
Laura