Open the makecode.com website and create a new Microbit project.

Create a variable called ‘action’, we will use this variable to store and remember a random action. In the on start block, set ‘action’ to -1 by adding this code:

let action = -1

Show: Microbit: How to create a variable

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In the Variables toolbox, create a new variable by clicking the 'Make a Variable' button.

Once you click this button a box will appear asking what you want to call your variable. Give it a name that reminds you what you will be using it for. For example, if you wanted to keep track of your score in a game, you would create a variable called 'score'.

Add a start countdown block and set it to 20000 milliseconds (which is 20 seconds).

let action = -1 
game.startCountdown(20000)

This means the player has 20 seconds to get as many correct actions as they can!

In the forever block we want to check if ‘action’ is equal to -1, if it is then we want to set ‘action’ to a random number between 0 and 2.

basic.forever(function () {
    if (action == -1) {
        action = Math.randomRange(0, 2)
    }
})

We choose a random number between 0 and 2 as that will give us three possibilities: 0, 1 and 2.

Next depending on what ‘action’ is now equal to, we are going to display an image on our Microbits telling the user what action they need to do.

• action = 0 means you should press the A button (arrow left)
• action = 1 means you should press the B button (arrow right)
  
• action = 2 means you should press the A+B buttons (arrows left and right)
  

Add the following code to check what 'action' is equal to and show the appropriate image.

basic.forever(function () {
    if (action == -1) {
        action = Math.randomRange(0, 2)
    }
    if (action == 0) {
        basic.showLeds(`
            . . # . .
            . # . . .
            # . . . .
            . # . . .
            . . # . .
            `)
    } else if (action == 1) {
        basic.showLeds(`
            . . # . .
            . . . # .
            . . . . #
            . . . # .
            . . # . .
            `)
    } else if (action == 2) {
        basic.showLeds(`
            . . # . .
            . # . # .
            # . . . #
            . # . # .
            . . # . .
            `)
    }
})