 Actually, you can see two of me right now, and that's because of our visual fields. So if I close one of my eyes and I put my hand out, you can do it as well, so I don't feel quite foolish, right? So I put one of my hands out, I can see it in my peripheral vision, and if I follow it around, I can see it all the way around, until there. So this is my peripheral field for my right eye, and likewise for my left eye, it's going to be about the same. So I actually have this region in the middle, that's my binocular field. And you can see two of me because you're actually looking right at me. And I can prove that to you, because if you just flick between one eye to the other, it actually looks like I'm dancing, I'm moving forward and back. So it is actually that imagery that's carried by the two eyes goes to your brain. Your brain uses that then to impose depth, right? This is an eye, it's actually my daughter's eye. You can see that my photography isn't great, the color is all wrong. But she actually has blue eyes kind of look gray there. She does have blue eyes, and the color of the iris has no real physiological function in terms of our capacity to see. Obviously there's aesthetic things to do with it. But it's really a muscle that enables, it adapts the amount of light that can actually enter the eye. But in terms of color, actually there's really only one pigment that codes for eye color and it's brown. It's a pigment called melanin. And people who have a lot of melanin, their eyes appear brown. And those who have blue eyes have no melanin. And the light actually is reflected off the iris. Same as the sky looks blue, it's the exact same thing, right? But the light passes through your pupil and it goes through the eye. It's about 15 millimeters, it passes through the lens. And then about 15 millimeters after that you reach the back of the eye. And the retina is where the light is, where it lands. And we have two types of sensory receptors that enable us to see. These are rods and cones, you've probably heard of them maybe before. So the rods enable us to see in the very dim light. So if you can imagine the last time you woke up in the dark, right? Probably this morning, if you're like me, had to get the half six train. But you can't see anything probably if the room is really dark for a little while. And then after a time, you begin to be able to make out rough edges. And really, that's as much as you can see with your rods. You can see a rough outline, you can see in grayscale. And also it takes a little while, they're not the quickest cells to activate. Whereas cones, just close your eyes and open them again. They're your cones, they're the cells that respond to high levels of light. So we can see in color, we can see with really high acuity, right? So the cones allow us to see it's high acuity, but they're actually concentrated in a particular part of our retina, which is called the macula. And at the center of it is the fovea centralis. And this is where they're found, the majority of them are, we've got three million of them in each of our eyes. And that's what we try to get our lens to focus on, right? And in fact, we do such a good job that we actually overdo it. So the light is over inverted. So on your retinas right now is a tiny little upside down version of me. And that's what actually gets carried to the brain. The brain sees everything upside down. And it's only after a period of time that if you were one month old babies, you would literally be seeing me like that, right? They see things upside down. And it takes a number of weeks for them to be able to figure out that we have to actually re-invert it. So luckily you're all grown-ups now, you're seeing me the right way up. Okay, thank you.