Not let our eyes be stolen by the altiplano that emerges and submerges in every direction. what does the phrase “let our eyes be stolen” mean? +

I don't know if you have any options, but I'd say the phrase "let our eyes be stolen" means something like distracted, or confused, or mislead.
I'd say the author wants to say that we shouldn't let the altiplano distract us from what we need to do or see.

Perpendicular line? no.