I hadn’t seen the part about it being memorable. Here’s something from real life that might help.
In my junior year of high school I was invited with 50 or so other high school juniors thinking of applying to a particular technical / engineering college to attend a one-week summer session where we could get a feel for the school, the curriculum and campus. We lived in dorm rooms for the week and ate in the school cafeteria.
Being young and away from home for the first time with little adult supervision all day (part of the freedom that they wanted us to get used to) one day at lunch we had a very small insignificant, really food fight. My one act of participation in the food fight (you have my word on this) was to remove a single tomato slice from my hamburger and fling it like a frisbee at a kid who saw it coming and ducked. The whole insurrection stopped almost immediately, but I noticed that my tomato slice had hit one of the drapes to one of the cafeteria windows… and stuck there.
It was almost un-noticeable because of the vivid colors and garish floral pattern of the drapes. But since I had tossed the thing and had seen it land, I could see it plain enough. I said nothing to anyone. The week passed, and we all went home.
A year and some months later I attended the college as an incoming freshman. The now blackened and withered tomato slice—the very one that I had thrown across the room more than a year earlier—was now almost a part of the drapery, stuck as tight as grim death (a really apt simile, if you could have seen that petrified tomato slice—and those really horrid drapes). The tomato lasted as long as I did at the college, three full years.
All that by way of setting up:
Wow! I remember that stain in your rug!