A ball on a slope

A sample post, written for the engine's tests. I'll begin with a simple picture: a ball rolling down a shallow slope. Driven by gravity, it seeks the easiest way down. The slope is full of ridges, channels and nubs, and they make the ball bounce and veer.

If thinking is something like the motion of that ball, then what we know is the terrain. This sample links back to recipes for a sample, and to casino samples, so that the margin has something to show around it.

fn roll(ball: &mut Ball, slope: &Slope) {
    ball.velocity += slope.gradient(ball.at) * DT;
}

That is all of it: a picture, a code block wider than a phone, and two links in.