A pure functional toaster would work one of two ways:<p>1) It would just be a solid box with no openings. Inside would be full of wondrous magic, but interacting with the outside world involves side-effects so interaction would not be allowed.<p>2) It would have a glass panel on the side, which you&#x27;d hold your untoasted bread against. A slice of toasted bread would pop out of the top. You&#x27;d never know where it came from, but you&#x27;d be happy that your original slice hasn&#x27;t been modified.