Update readme quickstart

README.md

@@ -16,18 +16,23 @@ Getting started with Tetris Gymnasium is straightforward. Here's an example to r
 actions:
 
 ```python
+import cv2
 import gymnasium as gym
+
 from tetris_gymnasium.envs.tetris import Tetris
 
-env = gym.make("tetris_gymnasium/Tetris", render_mode="human")
-env.reset(seed=42)
+if __name__ == "__main__":
+    env = gym.make("tetris_gymnasium/Tetris", render_mode="human")
+    env.reset(seed=42)
+
+    terminated = False
+    while not terminated:
+        env.render()
+        action = env.action_space.sample()
+        observation, reward, terminated, truncated, info = env.step(action)
+        key = cv2.waitKey(100) # timeout to see the movement
+    print("Game Over!")
 
-terminated = False
-while not terminated:
-    env.render()
-    action = env.action_space.sample()
-    observation, reward, terminated, truncated, info = env.step(action)
-print("Game Over!")
 ```
 
 For more examples, e.g. training a DQN agent, please refer to the [examples](examples) directory.