Ah the swirl I was wonder what that was called I have limit knowledge of burn patterns and what they mean why it's doing that and how to correct the problem.
What I was actually think with the spark plug was the rear port is to low in comparison to the front transfers and not getting g short-circuiting but the opposite I don't remember what that's called but can be really bad if it get a chance to blow by into the transfers. I read about it once.