I touched on this when I wrote
about Subspace itself, but it really belongs here for completion's sake, as they're two entirely different themes:
No need to worry
about it blending, either, as it's one of the few things in
Subspace (besides our heroes and the door itself) that exists in full red - and - white color (a palette choice different from Super Mario Bros. that would stick around for installments well into the future).