Or you’re on a worm of a young/green one who has zero spatial awareness and questionable lateral work.
Second the “gorgeous” and yes on straight walls, slants always gave me the heebies for the reasons mentioned. I’ve actually seen more than one horse fall on a slanted wall, never experienced it and don’t want to.
Where I live it would be very difficult to heat an indoor.
Honestly I don’t know why people want to. I boarded at a couple barns with heated indoors, and for the cost, it’s really not all that great. You’re gonna get it 45F, at most, before getting into a really exorbitant cost. But you can keep it around 25-35 easil,y, even when it’s -10F outside, with just good insulation and keeping doors shut during the winter.