 So obviously one of the major considerations you have to think about in a good UI design is color. So imagine that we come to these stop lights here. If you had a color blindness, all of these colors would look the same. So to be able to further distinguish them, you might add some symbols. So here we've got a forward pointing arrow, and that might represent go, a triangle sign, which might represent caution, and an octagon, which is similar to a stop sign, which means stop. And here we introduce color, and we know the color green to mean go, yellow to mean pause or slow, and red to mean stop. And if we combined all those things, we might have the most ideal version of color, which is complemented by symbology or pattern.