Aquascaping is tough to put into words. I realized that this video is actually done at a bad angle to show what I was trying to demonstrate with the triangle. because it is taken at an angel… It would have been better straight on.
The basic idea is that you have to imagine that your eye is going to want to follow along past the hardscape. Hardscape means any drift wood or rock work. You have to realize that the hardscape is cutting the space above and below it. This is also true with plants though not as heavily.
Something else to consider is how much open space is being used or not being utilized. You have to have some space open. this lets the eye rest. You will notice this in almost all winning aquascapes there is a certain area where there are no plants or it is left intentionally open. This was done for a reason. You need space. The key is dividing it up.