As you start to draw more grpahical shapes the visual outputs might be different from what you intended or even wrote in your code.
Depending on what order the computer executes your code can make a big difference visually.
This example will run without a compiler error. However, it will result in a Functional Error that draws different graphical outcomes.
Consider why the left-hand example has a large solid orange square in the back-drop when the right-hand example only has one small square in the foreground.
Try edit the code to generate the graphic in the right-hand visual.
Consider what lines of code might be effecting the visual difference.
Once you start typing code you can press the 'undo' button to go back a step. Or press the 'revert' button if you want to refresh to the orginal code.