My problem was that "Albert Heijn" is a dude's name. It does not exactly scream "we're talking about a real physical building".

For all I knew, the impossible problem we're solving could've been on a mathematical plane, named after mathematician Albert Heijn. "Sweeping" just as well can be used in an abstract sense.

Obviously, I did think of physically sweeping a physical floor first and foremost, but especially with the rest of the blog post being so entirely abstract, I had doubts on that for far too long, which did not make it easier to understand.