In this project, we'll start with our code from the last project (where we moved the aliens to the right), and we'll add moving the aliens back the left and increasing the speed as they get closer and closer to the bottom of the LED Matrix screen.
To do this, we'll need to create two new variables to track the direction of the aliens (+1 or -1) and the speed of the aliens (a multiple of the default speed we set in the last project).
Here is our initialization code:
And here is the code we will add to our game loop:
Here is what the full project code should look like at this point: