I laid a 6'x8' tarp across a flat spot in the pasture, anchored it down with some old pipe and wood posts, and went inside to change clothes after work. Harley look at it, snorted at it, but didn't get too close. I came back outside to find him about ten feet away staring at it...
I haltered him, brushed a little of the dirt off, and led him to the tarp. I walked over it, and turned to face him, tugging just a little on the lead rope.
You all know this point in the drill, right? This is where I was planning for a disagreement, and had entire intentions on getting him over the tarp, or at least showing interest. Approach and Retreat, but don't let him look away....
Harley reached his neck forward, sniffed at the tarp, hesitated, and took a step towards it. I tugged again, he stepped ON the tarp. Crunch! Noise it made when he stepped on it, and he hesitated, his head popping up to the sky. He then lowered his head a little, and STOMPED on the tarp with the remaining four hooves as he pounded it down. Every time after that, he walked across, with no hesitation, his "stomp" decreasing each time.
I hung the tarp over the paddock fence, and the wind caught it a little. Harley barely reacted to it. I stuck my hand inside the fold over the fence, and crunched it a little, to which he reached forward and put his nose on it, so I scratched his nose through the tarp.
Then I took the tarp in my hands, and held it up over my head like a flying cape. He finally spooked a little when the wind caught it, and shot away about fifteen feet before I got ahold of him, and kept him facing the tarp. Within another few minutes, he was standing a safe distance from the tarp while the wind was blowing it, and I was swishing it around by flapping my arms. He didn't seem phased by it much after the first reaction.
The Big Tarp Spook? Almost a non-event. I still don't really have my hands around this. This is the same Harley I had a hard time catching, that didn't trust me at all last year. He was terrified of everything. Now, something as scary as a blowing tarp hardly catches his attention. It's excellent, but I am still not entirely sure I understand it.