[VikingCoder]

Satellites also get side-views, not just top-down.

If you wanted to communicate more quickly, you would hang your clothes on a clothesline. Picture black and white sheets.

Day one:

01010011

Day two:

01001111

Day three:

01010011

So, that's 8 times faster.

Or you lay out a bunch of tiles... Tiles are tricky, because if someone asks, "Why are you changing what's on your roof?!" it's hard to answer. Sheets on a clothesline are plausible, though. "I'm doing my laundry!"