I haven’t been able to take my regular walk lately, so I offer you a Mystery Flower from last spring.
The Mystery Flower is the red stuff seen here in one of my wildflower bouquets. It was growing sporadically in the lawn of our old apartment building. In some neighborhood lawns, it had completely taken over.
I think in small quantities this flower is almost attractive, but I’m sorry to say that it makes lawns look horrible. It is, therefore, a plant most homeowners probably don’t want to see. My guess at its identity is in the comments.