The first diagram in that article is pretty ironic in an HN comment thread about Monty @ Xiph's stuff. Have you never seen his takedown of the "stairstep" drawing?
One of the central points of that video by Monty is that staircase drawings are a lie. It's not that they need to be explained, they need to be avoided.
This is a marketing page after all, explaining point-wise samples, reconstruction filters and "staircases" is way beyond scope.
Same as in images, pixels are not "little squares"