You know, what you might want to do is tie a blue tarp up in his stall so that he has to stand by it to eat. I know you'll have to force him in there at first, and go in there with him to boot, but he'll get used to it eventually. When I'm halter training my babies, I'll lay a tarp on the ground and sprinkle feed on it. Of course I weight the edges down with rocks and try not to do it on a windy day at first, but when they get used to it, they actually LOOK for tarps coz they know they're gonna get a treat.
Your post reminds me.. none of yall answered. Do you think horses can see blue? I cut my hand and put a neon colored blue glove on. Both of mine were taken aback at first and another horse spooky of it too.
He'll get used to one tarp in one place, but that doesn't translate to new tarps in new places ;~D
When I used to have hay out in the middle of the barn, he'd get used to walking by that tarp, but it didn't mean it wasn't scary if I showed him a different one.
Half of it is just for show. He doesn't bolt off on me when he sees one flapping, he just snorts and dances and likes to show off how cool he looks when he's all wound up. I think that's the required ritual all Arabians are taught at birth. ;~D