arrows <- and ->
1 part - https://scratch.mit.edu/projects/103732201/ 2 part - https://scratch.mit.edu/projects/103827477/ 3 part - https://scratch.mit.edu/projects/103838839/ 4 part - https://scratch.mit.edu/projects/104707764/ 5 part - https://scratch.mit.edu/projects/103097996/
