Thank you, Hank B!
I have a bamboo drop-down curtain outside my west kitchen window. It does get blown around a bit, but since there are spaces between the bamboo strips, it is'nt as good a "sail" as a solid sheet of material. Yet it block just enough to keep the kitchen cooler. It would also limit outside reflections, although I don't have that concentration problem anyway.
I recall an S-F story where the fans of a soccer team were angry at bad calls from a particular referee. Next game, all their game programs had mirrors on them.
Next time that ref made a bad call, they all shined their mirrored programs on him and he got incinerated.
I figure, say, 5000 fans with 10cm x 12cm mirrors shining the sun on him, gets him blasted with about 45 kiloWatts...more or less, kinda sorta, roughly, if my arithmetic is correct and assumptions anywhere near reality. So call it the power of 450 100 Watt light bulbs.
Terry, 230RN