this rename is absolutely stupid

docs/chapters/weightcontrol/rational.js

@@ -0,0 +1,32 @@
+setup() {
+  this.curve = Bezier.defaultCubic(this);
+  setMovable(this.curve.points);
+
+  const inputs = findAll(`input[type=range]`);
+  if (inputs) {
+    const ratios = inputs.map(i => parseFloat(i.value));
+    this.curve.setRatios(ratios);
+
+    inputs.forEach((input,pos) => {
+      const span = input.nextSibling;
+      input.listen(`input`, evt => {
+        const value = parseFloat(evt.target.value);
+        span.textContent = ratios[pos] = value;
+        this.curve.update();
+        this.redraw();
+      });
+    })
+  }
+}
+
+draw() {
+  clear();
+  const curve = this.curve;
+  curve.drawSkeleton();
+  curve.drawCurve();
+  curve.drawPoints();
+}
+
+onMouseMove() {
+  redraw();
+}