diff --git a/html/bars.tsx b/html/bars.tsx
new file mode 100644
index 0000000..e693db2
--- /dev/null
+++ b/html/bars.tsx
@@ -0,0 +1,98 @@
+import { JSX } from "preact";
+import { Main, render_and_copy } from "./common.tsx";
+
+const Bar = ({
+    color,
+    animation_time,
+    side,
+}: {
+    color: string;
+    animation_time: number;
+    side: "left" | "right";
+}): JSX.Element => (
+    <div class="bar">
+        <div
+            class="bar-inner"
+            style={{
+                transform: `translateX(${side == "left" ? -100 : 100}%)`,
+                backgroundColor: color,
+                animation: `${animation_time}s alternate-reverse ease infinite spin`,
+                outline: `1px solid ${color}`,
+            }}
+        ></div>
+    </div>
+);
+
+function coprime(a: number, b: number): boolean {
+    if (a == b) return false;
+    for (let i = 2; i < Math.min(a, b); i++) {
+        if (a % i == 0 && b % i == 0) {
+            return false;
+        }
+    }
+    return true;
+}
+
+function next_coprime(ns: number[]): number {
+    if (ns.length == 0) return 2;
+
+    for (let a = ns.at(-1) ?? 0; ; a++) {
+        let good = true;
+        for (const b of ns) {
+            if (!coprime(a, b)) good = false;
+        }
+        if (good) return a;
+    }
+}
+
+function gen_coprimes(to: number): number[] {
+    if (to <= 0) return [];
+    if (to == 1) return [2];
+
+    const xs = gen_coprimes(to - 1);
+    return [...xs, next_coprime(xs)];
+}
+
+const BarPair = ({
+    color,
+    animation_time,
+    num_bars,
+}: {
+    color: string;
+    animation_time: number;
+    num_bars: number;
+}): JSX.Element => (
+    <div class="bar-pair" style={{ height: `${(1 / num_bars) * 100}%` }}>
+        <Bar color={color} animation_time={animation_time} side="left" />
+        <Bar color={color} animation_time={animation_time} side="right" />
+    </div>
+);
+
+const Bars = ({ colors }: { colors: string[] }): JSX.Element => (
+    <Main>
+        {...colors.map((c, i) => (
+            <BarPair
+                color={c}
+                animation_time={2 ** i * 0.1}
+                num_bars={colors.length}
+            />
+        ))}
+    </Main>
+);
+
+render_and_copy(
+    <Bars
+        colors={[
+            "#FF6961",
+            "#FFB347",
+            "#FFFF99",
+            "#77DD77",
+            "#ADD8E6",
+            "#B19CD9",
+            "rgb(var(--color-longan))",
+            "rgb(var(--color-mango))",
+            "rgb(var(--color-strawberry))",
+            "rgb(var(--color-cherry))",
+        ]}
+    />
+);
diff --git a/html/hot_people_who_eat_croissants_are_dangerous.tsx b/html/hot_people_who_eat_croissants_are_dangerous.tsx
index 818ac0a..740622f 100644
--- a/html/hot_people_who_eat_croissants_are_dangerous.tsx
+++ b/html/hot_people_who_eat_croissants_are_dangerous.tsx
@@ -23,7 +23,7 @@ const wheel_style = (
 });
 
 const get_delays = (...lengths: number[]): number[] => {
-    let out = [0];
+    const out = [0];
     for (const l of lengths) {
         out.push((out.at(-1) ?? 0) + animation_length(l));
     }