I don’t see the problem. Your statements are all correct and your conclusions also correct. But then you said you were unable to eliminate any other options. This is my least favorite part of the game competitively and favorite part when just soloing a puzzle. There must be a single non-ambiguous solution. You would need to try a different experiment to see what else machine code B can give you to whittle down your options. But knowing it must eliminate options can help you get to an answer without even checking.
You correctly reasoned code B is not testing blue because it cannot be the largest number.
If you test 455 against B and it came back as true, that would mean that it must be purple is 5 and thus yellow is 5 giving 355 and 455 as possible solutions with the test only checking the purple number that would leave no way to distinguish between the two possible blues and is invalid. So we know this wouldn’t be the result no can ignore the change machine code B is checking purple.
If you test 455 against B and it came back false this would mean that it was testing yellow. It would then mean yellow must be 5 and thus so is purple. And back to the same result as before that it cannot distinguish between 355 and 455 with this result.
So the only thing left is to test something else there. Such as 344. If you test a 344 and it came back false then you know it is testing purple because that resulted in a change. This leaves 355 and 455 both as options. But if you test 344 and it comes back true, then the only way to be true both times is if the yellow is a 4 and thus so is purple. There was only one option that had x44 as a solution.
Thus it was possible to solve 344 without actually doing the machine code test just because you know the code test must be able to give a single final answer.
I’ve solved way too many 6 code Turing machines in one or two rounds purely based on the nature of the possible results must distinguish a single final answer and getting the solution not by testing by but the nature of the algorithm that generated the solution. Fun for solo play but pretty frustrating for opponents. Especially since there is a strong element of luck in getting initial info that allows a cascade deduction not knowing what the result will be till you try the first number.
I hope this helped! Typed up while coming off a nap and on tablet so forgive anything that didn’t get formatted right in my quick reply.
