The codepen project linked here is a relatively simple example that uses virtually no HTML syntax; it illustrates a light blue circle and separately illustrates three other black shapes that resemble the eyes and mouth of a smiley face. The eyes regularly flatten themselves horizontally every five seconds to simulate blinking, and the eyes and mouth dynamically reposition themselves within the circle's bounds to simulate the face angling itself to keep looking at wherever the viewer is currently holding their mouse's cursor.
The project features a similar squishing process that comes into play when the left and right edges of the window containing the white space are compressed together. This is hard to see in browser programs that enforce a limit on how narrow their application windows can be, but the "Change View" function on codepen lets the user choose an alternative layout that moves the adjustable dark gray area to one of the edges of the screen. For more information click here https://i.redd.it/e32tp7lrlsl21.gif.