But it's all about what's happening in this instant. In this instant. And to think about why that is not a super easy problem to address with traditional algebra, let's draw a little graph here. So on this axis, on this axis, I'll have distance. So and I'll say y is equal to distance. I could have said d is equal to distance, but we'll see, especially later on in calculus, d is reserved for something else. We'll say y is equal to distance.