Migrate docs from the other repo

docs/lessons/screen-wipe/activity.md

@@ -0,0 +1,90 @@
+# screen wipe blocks activity
+
+Clear the screen by pressing buttons on the micro:bit 
+
+### ~avatar avatar
+
+### @video td/videos/screen-wipe-0
+
+This activity will teach how to clear the screen by pressing button A on the micro:bit.
+
+### ~
+
+You can use the clear screen` function to turn off all the LED on the screen. Let's illustrate this concept with a small script where the user has to press the button A to turn off the screen. Let's start by adding the code to show an animation.
+
+```blocks
+basic.showLeds(`
+    # # # # #
+    # # # # #
+    . . . . .
+    . . . . .
+    . . . . .
+    `)
+basic.showLeds(`
+    # # # # #
+    # # # # #
+    # # # # #
+    # # # # #
+    . . . . .
+    `)
+basic.showLeds(`
+    . . . . .
+    . . . . .
+    # # # # #
+    # # # # #
+    . . . . .
+    `)
+basic.showLeds(`
+    . . . . .
+    . . . . .
+    . . . . .
+    # # # # #
+    # # # # #
+    `)
+```
+
+We add another line of code that registers an *event handler* `on button pressed` *A* and calls `clear screen`.
+
+```blocks
+basic.showLeds(`
+    # # # # #
+    # # # # #
+    . . . . .
+    . . . . .
+    . . . . .
+    `)
+basic.showLeds(`
+    # # # # #
+    # # # # #
+    # # # # #
+    # # # # #
+    . . . . .
+    `)
+basic.showLeds(`
+    . . . . .
+    . . . . .
+    # # # # #
+    # # # # #
+    . . . . .
+    `)
+basic.showLeds(`
+    . . . . .
+    . . . . .
+    . . . . .
+    # # # # #
+    # # # # #
+    `)
+input.onButtonPressed(Button.A, () => {
+    basic.clearScreen()
+})
+
+```
+
+*Run* the script in the simulator or on the micro:bit to see how this works!
+
+### ~avatar boothing
+
+Excellent, you're ready to continue with the [challenges](/microbit/lessons/screen-wipe/challenges)!
+
+### ~
+