So in this particular case, it's this carbon number two that is puckered. So this is the carbon number two that we have in this diagram and these other atoms. So this carbon here, this carbon here, this carbon here, and this oxygen here, these lie along the same exact plane. And likewise, in the other type of conformation, c three endo, where the third carbon is puckered, this becomes the third carbon. And so now this carbon number one, two for this oxygen will lie along the same plane. And carbon number three is the one that is puckered.