[planetpluta]

> Take, for example, "Day," which is even, and "Say," which is odd. Since the "-ay" suffix is consistent, it indicates that "S" is the first letter in the target word.

Am I missing something? Given that information, couldn’t the D+a or D+y be correct?

(I understand those cannot be correct because of “May”, but not from the consistent suffix alone)

[svat]

The sentence is missing the example of "May", as you observed. It should say:

> Take, for example, "Day" and "May", which are even, and "Say", which is odd. Since the "-ay" suffix is consistent, it indicates that "S" is the first letter in the target word.

(Because as "Day" and "May" have the same parity and different from "Say", it must be that "D" and "M" must have the same correctness and different from "S", and as only one letter can be correct, that letter must be "S".)

[cyborgx7]

You're correct. In fact I'm not seeing any two probe words that will give you a definite piece of positive information, without taking into account a third word.

I made my own mistake when trying to figure out this puzzle, that I didn't notice until your comment prompted me to go back and check through it again. I thought after the three even words, the solution had to BAY or all three even words had to be zeroes. But without using any of the odd probe words, words starting with BU- are also still a possibility.

[pimlottc]

I think that line was meant to help you understand how the algorithm works internally, not what information was revealed the player.