 Okay, so we have this activity in the physics for education majors course, and they use one of these. So it's a mylar square on a white sheet of paper, and then they shine a flashlight at it. And then they look and see who can see this as shiny bright. It's a good activity. But you have to have the room dark. And so in order to compensate for a non-dark room, I, you can't buy these things. I built this. So let me show you inside the box. So there's a, it's black inside, and there's a mylar square in there. And then back here, I have a flashlight, and it's connected to a battery so I can turn it on. And then when I close this, when I close this, sorry, I have a window so you can look and see what it looks like as the flashlight person or the side person or the opposite person. So let me go ahead and turn it on and show you how it works. Okay, the flashlight's on. So let's pretend like where the person holding the flashlight, I'll open the window and we'll look in there. Let's see. Oh, the flashlight's on. Awkward. Okay, I guess my battery, oh no, there it is. Okay, sorry. Okay, so looking in there, you can see the white paper around it, but the mylar, you can see how it appears. I don't want to say it. Let's look at the side person, oops, get the angle right. There it is. So there you can see the mylar and the paper. Now let's look at the opposite person. There you go, dark room in a box. Check it out. Dark room in a box. John, that was for you and you know who you are.