Tangent and cotangent, it might have been Marwazi, or it might have been another mathematician named al-Buzjani, who came a little bit after, or a lot, depending on a human scale, but was also based in Baghdad. And together, they came up with the six, the six trigonometric functions. They weren't contemporaries of each other, but they both made significant contributions to what we now call trigonometry, including many of the trigonometric identities that we now learn in high school. Now, you also have physicists, mathematicians, astronomers like al-Hazen, and he is credited as getting one of the more sophisticated views of how light and vision works. These are some quotes from al-Hazen. From each point of every colored body illuminated by any light, issue light and color along every straight line that can be drawn from that point. This is a fairly sophisticated view of how light actually works.