It’s high July in Mason, in the heart of the Hill Country. Several thousand have turned out for the town’s annual rodeo roundup parade, a splendidly small-time procession that circles the county courthouse twice before dispersing into a subworld of barbecue, corn dogs, funnel cakes, and handicrafts. Flags flutter. Floats rumble by featuring the camo-themed Yonker Brothers Meat Market & Processing, the rodeo queen’s court, and, in case you have forgotten what part of the country you are in, “Texans for Trump.”The parade is picture-perfect. It is also perfectly predictable, except for one wildly singular participant: a blinding collision of dystopian triangles known as the Cybertruck. Though it’s hard to tell by looking at it, the vehicle is an electric pickup made by Tesla, one…