Getting around a traditional Chinese city, village or home is all about going through gates. Thus "going through a gate" is a primary metaphor used to describe learning something or getting something done. It is also a primary metaphor for describing movement of qi around the body. For instance, the shoulder and the hip each have a major gate that allows qi to move between the limbs and the torso.
I did a lot of skateboarding in my teens. Every day I skated steep hills with (by todays standards) large 70 millimeter Kriptonics wheels. I'm what the kids today call O.G. (Old Gangster). There are very few people with this particular experience around. Downhill skiers and snowboarders have some comparable skills, so I can at least communicate with them, but snow is softer than concrete and there aren't a lot of cars on the slopes.
Skateboarding was a gate I passed through to get to my current understanding of internal martial arts. It still informs my practice. When I heard the taijiquan saying "You must go left in order to go right" I understood it immediately, skateboarding works the same way. If you are going to make a high speed 90 degree turn into traffic you have to feel your pathway through space and along the ground before you make the actual sequence of turns that will get you into the little space between the the moving cars and the parked cars. Just turning to the right will get you squished.
Now when I teach, I'll say something like "Do this," or "Copy me," but nine times out of ten the student doesn't quite do what I'm hoping they will do. So I'll describe what I'm doing, or let the student feel my torso moving. But often they still don't "get it." I think, o.k., if I was in their body I would just do "this" and "this" and "that other thing." From where I'm standing I can see exactly what they need to do to get to where I am. It is as if there were a stone bridge that, if they could see it, they could just walk across.
But they don't see the bridge. So I have a choice. I can either keep trying to get them to see the bridge, or I can take them through some of the gates I passed through on my way to achieving my current skill level.
I do have some memory of the hundreds of gates I passed through to get to my current skill level in internal martial arts. From a teacher's point of view, the only proven method for getting to where I am, is to pass through all the same gates I passed through. However, it isn't realistic for me to ask all my taijiquan students to take up downhill skateboarding.
What most teachers do at this point is to make up a list of gates (exercises, experiences) that will hopefully be a shorter route to excellence than the one the teacher took to get there. Some of the gates I teach are ones I passed through myself, some are gates that I think are improvements on the ones I passed through, and some are gates I put there because I'm hoping that the student might notice the stone bridge off to their left on the way through.
Every teacher, whether he is rigid, traditional, experimental, or inspired, has to decide whether to point to the stone bridge, or guide students through gates. I wish I understood this when I first started studying gongfu.