I pictured a smooth red rubber ball about the size of a baseball on my kitchen table. The “person” was more of an invisible force, not explicitly male but definitely not female. That might be male bias, or subtly thinking of myself doing it (combined with playing too many physics engine video games where your disembodied self pushes things around).
All of this was pretty vague though, like I didn’t really imagine the details of the room or the exact path of the ball other than knowing it would roll off and bounce on the floor.
I imagine it’s because it’s the simplest, most common type of ball that you commonly see described as such. Like, baseballs and basketballs and soccer balls and beach balls exist, but out of context they’re typically called that rather than just “a ball”. So, a simple round ball. Giving it a pattern requires some extra thought, and of the solid colors red seems like the most common (think dodgeballs).