Now that we understand that sigma bonds are free to rotate as much as they want, it turns out that there's a unique way to visualize this rotation. And that visualization technique is called the Newman projection. Alright? So Newman projections are all about finding the different energy levels that conformers can make by rotating a sigma bond. Okay? So maybe you recognize this drawing. This drawing is the same drawing that I had before when I was talking about conformers and I was saying that you could have an S transhexane or an S cishexane. Okay? But it turns out that it's kind of difficult to visualize how those are different in energy. Energy is kind of an abstract concept right now. We haven't really defined it very well, but just think about it that if something is very high in energy, that's not going to make it very stable. Okay? So in this case, it's not easy to tell which one is lower energy and which one is higher energy and that's why we want to have a new way to visualize this. So what we say is, hey, imagine that your eyeball was right on this plane. So imagine that this is your face and this is your nose and those are your lips and obviously you're just an amazing looking dude. Wow. Okay. So I need to stop what I'm doing because that's really terrible looking. So imagine that that's a person. Don't imagine that's you. I don't want to get traumatized. And you're looking at that bond straight down the line, straight down that bond. What you would actually see is, you would see a carbon in the front. Let's say that's your red carbon. And you would also see a carbon in the back. Let's say that's your blue carbon. You would see them overlapping each other. You'd see one if you're looking right down that bond, you'd see one in the front, one in the back. So you would see that this would be your front one and then the one in the back would be represented by that circle. Okay? And basically what Newman projections allow you to do is to visualize, okay, where are the groups on the front carbon oriented and where are the groups in the back carbon oriented and how are they related to each other? And with Newman projections, you're allowed to rotate around that bond in a three-dimensional way. Okay? So basically, if you were to look down that bond, what you would see is that your big groups, this ethyl group here and this ethyl group here, would be on opposite sides of these carbons. Because as you can tell, if you were to draw your dotted line, they're on opposite sides of the fence. So basically, they'd be really far away from each other. Okay? But then if you look at Sis, Sis is different. Sis, if I had the same thing where my eyeball is looking, I would still see one in the front. Oh, just a second. Wow, red. I would still see one in the front and one in the back. But what I would also see is that now the big groups are overlapping each other. Okay? Instead of being on opposite sides, they're overlapping and that has a huge difference in how stable these molecules are, how stable these conformations are.