diff --git a/other/poyopoyo-pudding.hpp b/other/poyopoyo-pudding.hpp
new file mode 100644
index 00000000..37d9cc83
--- /dev/null
+++ b/other/poyopoyo-pudding.hpp
@@ -0,0 +1,57 @@
+/**
+ *  🍮 PoyoPoyoPudding 🍮
+ *
+ *  - 最大 10 層までプリンを重ねられる。
+ *  - 各層には「甘さ (0-100)」と「弾力 (0-100)」を保持。
+ *  - addLayer でプルプルを追加、eatTop で一口たべる。
+ *  - shake でランダムに弾力が変わる（ぷるん♪）。
+ *  - operator<< で可視化。🍮
+ */
+struct PoyoPoyoPudding {
+  struct Layer {
+    uint8_t sweetness;    // 0-100
+    uint8_t springiness;  // 0-100
+  };
+
+  static constexpr size_t kMaxLayers = 10;
+
+  // ---- 状態 ---- //
+  std::array<Layer, kMaxLayers> layers{};
+  std::size_t top = 0;  // 現在の層数
+
+  // ---- 挙動 ---- //
+  bool addLayer(uint8_t sweet, uint8_t spring) {
+    if (top == kMaxLayers) return false;
+    layers[top++] = {sweet, spring};
+    return true;
+  }
+
+  bool eatTop() {
+    if (top == 0) return false;
+    --top;
+    return true;
+  }
+
+  void shake() {
+    mt19937 rng{static_cast<uint32_t>(
+        std::chrono::steady_clock::now().time_since_epoch().count())};
+    std::uniform_int_distribution<int> dist(-5, +5);
+    for (std::size_t i = 0; i < top; ++i) {
+      int v = static_cast<int>(layers[i].springiness) + dist(rng);
+      layers[i].springiness = static_cast<uint8_t>(std::clamp(v, 0, 100));
+    }
+  }
+
+  // ---- デバッグ／鑑賞用 ---- //
+  friend ostream &operator<<(ostream &os, const PoyoPoyoPudding &p) {
+    os << "🍮 PoyoPoyoPudding (" << p.top << " / " << kMaxLayers
+       << " layers)\n";
+    for (size_t i = p.top; i-- > 0;) {
+      const auto &L = p.layers[i];
+      os << "  ├─ Layer " << setw(2) << i << " | Sweet " << setw(3)
+         << int(L.sweetness) << " | Spring " << setw(3) << int(L.springiness)
+         << '\n';
+    }
+    return os;
+  }
+};