What I did for obstacles is I took my truck out on some logging roads into the woods and found fallen logs that I would lift into the bed. I got some PVC pipe, wooden 2x4s, tarps, garbage bags, old tires from the junkyard, old buckets/barrels, etc.
If I was going to make the tarp thing at my house, I would probably put a couple tarps over my round pen tall enough for the horse to ride under and attach some trash bags to it. You could also find a tree branch and hang strips of tarp/plastic/trash bags to walk under.
For the log jump, I would just go find a log and prop it up on some cinderblocks, tires, cavaletti blocks, or anything like that.
You could also make a jump by setting up some tires in a row and filling them with dirt or sand, or using the 2x4s or PVC pipe propped up like a crossrail.
You could also try tying sticks to the edge of the pen and putting a bunch of trash bags/plastic walmart bags on the end of them to walk under.
Get a rope and drag a tire or barrel around...
Just get creative...There is a lot you can do!
Pssh.I didn't pick up the wrong lead
It's called a counter canter...
...A very advanced maneuver.