moving out outdated js docs

olddocs/js/lessons/pong/activity.md

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+# pong activity
+
+Building a game of pong with sprites.
+
+### ~avatar avatar
+
+### @video td/videos/pong-0
+
+Welcome! This tutorial will teach you how to build a simple pong game using sprites.
+
+### ~
+
+The game works as follow: the user moves a paddle on the left of the screen and a ball bounces on the other side. Let's start by creating the 2 sprites.
+
+```
+let paddle = game.createSprite(0, 2)
+let ball = game.createSprite(4, 2)
+```
+
+Let's make the ball start with an angle.
+
+```
+ball.setDirection(-45)
+```
+
+The user will control the paddle by pressing ``A`` to go up and ``B`` to go down. Let's add ``on button pressed`` event handlers to do that.
+
+```
+input.onButtonPressed(Button.A, () => {
+    paddle.changeYBy(-1)
+})
+input.onButtonPressed(Button.B, () => {
+    paddle.changeYBy(1)
+})
+```
+
+Let's add a ``forever`` loop to start the main game logic.
+
+```
+basic.forever(() => {
+    // Leave the sprite on screen for a little while.
+    basic.pause(400)
+    // Let's move the ball in whatever direction it is currently going.
+    ball.move(1)
+    // The ball might be on the left side of the screen (``x = 0``), let's test for that.
+    if (ball.x() == 0) {
+        // Let's add a little pause to let the user know that the ball is on the side.
+        basic.pause(400)
+        // If the paddle is not at the same ``y`` coordinate, it missed the ball and we can trigger a game over. If not, we add a point to the score.
+        if (paddle.y() != ball.y()) {
+            game.gameOver()
+        } else {
+            game.addScore(1)
+            basic.pause(500)
+        }
+    }
+    // The ball moved and might be on a side, let's make sure it bounces.
+    ball.ifOnEdge_Bounce()
+    // If the ball is on the left side, slide it forward to change slightly the bouncing mechanics.
+    if (ball.x() == 0) {
+        ball.changeXBy(1)
+    }
+})
+```
+