I was just wondering how on Earth do I know the word matta already. This happened before with some random words. And I realised it's because of...my grandma's quirks, I guess! Living in Sweden influenced her badly enough that she now uses some kind of a mishmash of her native tongue and Swedish when speaking to people who don't speak Swedish (such as myself), apparently teaching them a few words along the way! So, if you're asking yourself why am I exactly posting this, it's because: beware, you never know with grannies, they all bear a tendency to become unintentional superheroes...
Speaking of "Den röda mattan", and reading here some explanations about the article Den, the plural or definite form of adjective röda and the difinite noun mattan, it occurred to me in my mind that the Swedish author August Sringberg wrote a novel titled "Röda Rummet".
Now I am just wondering why there is no article "Det" in front of the adjective röda and the nous rummet, if I try to follow the description and function of the Swedish grammar. Tack så mycket.