 Okay, so let's try another one of these Jericho-Primer questions. This one asks, which one of these structures depicts trans-isomer and which ones depict a cis-isomer? Okay, so let's just go through each one and see which ones are trans and which ones are cis. Okay? There's all one-two diamethylcyclohexane, some isomer of that. So let's go ahead and draw the bond line form of cyclohexane. In fact, I think this is the easiest way to go about doing this, is that you just depict this form on a bond line form, okay, because it's easier to see. But anyway, so what I'll do is I'll label this top right atom, always, that top right carbon is one, and then go around the ring, one, two, three, four, five, six, like that. And so let's just go ahead and do that with all of them. And like I said, I label this one as one and go to the right, like a claw. So those are the two atoms we're going to be putting the metal groups on, and we'll just depict which ones are cis and which ones are trans now, okay? So whenever I have an axial on this one position, I'll put it facing towards me. So that means that the equatorial is the H there, and it is back. So here this is axial, this metal is axial, but it's pointed down, right? The H is actually pointed up there, so the metal is down. So in this case it's back. So if I were to take this and turn it, this metal would be poking me in the eye, but the other metal would be away from me. So in fact, A in this case is trans. So let's do B now. So it's the same general molecule, we just got a different stereoisomer of it. So here in this case we've got the hydrogen as the axial, so the hydrogen would be pointing towards us. So in that case the metal is pointing away from us, and here hydrogen is down axial. So whenever the point is up, that means the axial is up. Whenever the point is down, the axial is down. So the methyl group here, since the hydrogen is down, the methyl group has to be up. So like that. So that one is trans. So the first two are trans, which is interesting because we have a 1-2 axial, axial relationship in the trans and a 1-2 equatorial-equatorial relationship in the trans, and you'll see that. So this one is axial-equatorial, and this one's equatorial and axial, and probably you've already predicted that they're going to both be cis, but let's just go ahead and show that. So there's our cyclohexane ring. Remember at 1, if it's axial, it's pointed up on our cyclohexane ring and wedge. Hydrogen is down and equatorial. Hydrogen is down and axial here, so the methyl is up, so hydrogen. So since this is up, so this is up-axial, this is up-equatorial, it's going to be cis. So c is cis, and in fact this one's cis, but while this one just flipped over like that, you want to think about it that way, or this one ring flipped, and if you want to think about it that way, that's what's happening here between the two isomers like that. And on both of them, well, this one is going to be much more favorable to go that way, because we've got two equatorials here, and here we've got two axioles, but this one, neither one of them is more favorable. So let's just go ahead and finish this off. Hydrogen is up, so that means the methyl is down. So here we've got one axial, one equatorial, one axial, one equatorial, so neither one of them is more stable than the other one. So hopefully that solves all of your conformational chair isomer questions.