From this article we will begin the Fourth course in Code.org code studio. We will look at all the stages except the unplugged activities. If you already have an account on Code.org you can access this stage in code studio from the link below.
https://studio.code.org/s/course4/stage/2/puzzle/1
Try to solve all the levels in this stage. If you get stuck at any level, you can see the solution on this page.
Below are the images of each level along with the code needed to complete that level.