moving turtle examples

docs/projects/turtle-scanner.md

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+# Turtle Scanner
+
+## Setting up your project
+
+This project uses an **microturtle** Extension. You'll need to add it to your project to make it work.
+
+* create a new project
+* click on the gearwheel menu and click **Extensions**
+* select the **microturtle** extension
+
+After the project reloads, you should see the **turtle** category in the blocks.
+
+## Code
+
+The turtle scans the display over and over again.
+
+```blocks
+turtle.setPosition(0, 0)
+turtle.turnRight()
+turtle.setSpeed(20)
+basic.forever(() => {
+    turtle.forward(4)
+    turtle.turnRight()
+    turtle.forward(1)
+    turtle.turnRight()
+    turtle.forward(4)
+    turtle.turnLeft()
+    turtle.forward(1)
+    turtle.turnLeft()
+})
+```
+
+```package
+microturtle=github:Microsoft/pxt-microturtle#master
+```