This block works for EV3, SPIKE™, Zappy, and Ruby!
Comments are used to document the program and remind programmers of what tricky things they just did with the code.
Another way to add comments, especially for longer, more detailed ones, is to right-click a block (any block!) and select 'Add Comment'. A question-mark (?) icon will appear on the block, which can be opened to reveal a note in which you can write as long an explanation as you wish:
Tip: you can enlarge or shrink this note as much as you want by grabbing its corner and 'dragging' it to change the note's shape and size. If the note is small, you can scroll up and down inside it. These notes can be opened and closed by clicking the (?) icon, and can be moved around, too!