When sitting on a car or bus and watching trees without following them is most of the technique done. It is like stereoscopy, but without helping gadgets.
It is about how to join the eyes together properly and then maintain that during whatever activity. Then after weeks months, there start flashes of lights, like actual lighting during lighting storm, it can be seen happen with regular eyes.
These are signs for opening of an important cavity. Without that cavity open there won't arise any breath perception, thus that can be an issue when people won't believe what being said.
Point is, the initial practice is to get the light of the mind enter to the visual field past the limbic system and then objects will be seen differently - with depth and uniformly. And it won't happen by itself when the signs are happen then one day you can make it happen, it is voluntary and you suddenly know what to do in order to make it happen. So no skipping nor cheating possible.
i like to add the more you open up, the more things you do voluntarily, the quiescence or background automatic rulebound meditation is only a part.https://en.wikipedia.org/wiki/Neocortex wrote: The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian cerebral cortex involved in higher-order brain functions such as sensory perception, cognition, generation of motor commands, spatial reasoning and language. The neocortex is further subdivided into the true isocortex and the proisocortex.