1. Create a row of 9 space aliens using the "Clone" block and just one sprite. Center the row on the X axis, with about 40 steps between each alien. 2. Create 4 more rows below the first row to form a 4x9 grid of aliens. 3. Bonus: can you make the aliens all move together to the right 10 steps, pause, then back to the left 10 steps? 4. Bonus: can you make them move right 10 steps 5 times, then back left 10 steps 5 times? 5. Bonus: can you make them all move down after the right - left steps? can you keep this continuous until the very lowest alien hits the bottom of the screen?
