diff --git a/README.md b/README.md
index 3a0abf4..06633b2 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,8 @@ The classic Snake game. It runs in your web browser from a single file and works
 
 - **Arrow keys** move the snake.
 - Eat the **red food** to grow and score a point. The snake speeds up a little each time it eats.
-- The game ends if you hit a wall or your own tail.
+- There are no deadly walls: go off one edge and the snake comes back in on the opposite side.
+- The game ends if you run into your own tail.
 - On the Game Over screen, click **Play Again** or press **Space** or **Enter** to restart.
 - Press **P** to pause and resume.
 
diff --git a/index.html b/index.html
index 943eba4..80b77e2 100644
--- a/index.html
+++ b/index.html
@@ -83,7 +83,7 @@
     <div id="startScreen" class="overlay">
       <h2>Snake</h2>
       <p>Use the arrow keys to move.</p>
-      <p>Eat the red food to grow. Don't hit the walls or yourself!</p>
+      <p>Eat the red food to grow. Go off one edge to come back on the other side, but don't hit yourself!</p>
       <button id="startBtn">Start</button>
       <p class="help">or press any arrow key</p>
     </div>
@@ -184,14 +184,17 @@
         // Use the next queued turn, if any (lets quick key presses register one per move).
         if (inputQueue.length) direction = inputQueue.shift();
 
-        const head = { x: snake[0].x + direction.x, y: snake[0].y + direction.y };
+        // Going off one edge brings the snake back in on the opposite side.
+        const head = {
+          x: (snake[0].x + direction.x + GRID) % GRID,
+          y: (snake[0].y + direction.y + GRID) % GRID,
+        };
         const eating = food && head.x === food.x && head.y === food.y;
 
         // The tail moves away this turn unless we're eating, so it's safe to move into.
         const body = eating ? snake : snake.slice(0, -1);
-        const hitWall = head.x < 0 || head.y < 0 || head.x >= GRID || head.y >= GRID;
         const hitSelf = body.some(s => s.x === head.x && s.y === head.y);
-        if (hitWall || hitSelf) {
+        if (hitSelf) {
           gameOver();
           return;
         }