How would yopu define a sunbeam?
Yes, direct sun; good point!
You will be interested to learn that when I created the rules, I was thinking specifically of the antipodeans. My original description referred to how the great masters actually designed their homes to take advantage of a North-facing window. I changed it to European homes, not knowing for sure if there were any Australian, Indonesian or South African great masters back in the day.
I ended up shortening the description considerably before it went "live."