When i was a young boy I remember looking up at the stars in the night and once or twice suddenly feeling how deep space was! It was like looking at a picture on the wall and suddenly realizing it is a window after all and I am looking a deep landscape! For me space was always like a picture and then it became deep. Too bad I couldn't always see it that way!
Maybe natural mind is like that? Even after instructions, it appears like a picture, maybe a small circle like a weak lamp casts at midnight? Maybe true rigpa moment is when the vivid waking up to depth and vastness occurs?
Other things like Dharmakaya are maybe like that too...a picture being naturally replaced when the time comes naturally with direct truthful feeling like a thunderbolt?
When I was a young boy, I remember looking up at the sky from a hillside and my eyes trying to bore through the sky like a drill! Later I learned this was an official practice! Maybe most official practice teachings is based on young boy experiences?
I'm just really guessing!