In front of a door to a cellar full of gold, there stand three guards. One of them tells only truth, the second one tells only lies and the third one smashes the face of anyone who dares to ask stupid questions.

Thanks for nice riddles!

Bill: Pink 7 + Grey 8 = 15 … so Pink with 7 arms would be telling the truth …

By the way, I love all of them, I used to do the old ones on J&S (a french magazine) with lots of true/lie tellers and other special characters (fool: sometimes true/sometimes lier, galactic perroquet: he was true/lier depending on the previous sentence of the problem), really nice ones.

All liars have 7 arms. If Gray is a 7-armed liar, then its statement is false, so Lavender cannot also have 7 arms, and is therefore a truth teller. But if Gray is an even-armed truthteller, then its statement is true and Lavender must also be an even-armed truthteller. Lavender must be a truthteller either way! Based on Lavender’s true statement, Turquoise must also be an even-armed truth-teller, making Pink a 7-armed liar.

So Pink has 7 arms, Gray has 8 arms, Lavender has 6 arms, and Turquoise has 8 arms.

Red says he has nine arms. If he had an even number, he would be truthful of that and not claim he has an odd number of arms, therefor he does have an odd number of arms, but not nine of them, and what he said about blue (that blue has 8 arms) cannot be true either. Since blue lied about how many arms it had, it must have an odd number of arms. And the green is already lying. So only the striped one told the truth (I have eight arms, and none of you do.)

I didn’t do the others.