I'm a stickler for correct physiological training and development, and one of the simplest ways to address it with horse training is the dressage pyramid. I've recently come across a diagram with sketches of the horse's posture at each stage, and after looking at it for a while I decided I should have photographs of each of the stages... So I created my own pyramid with photographs to illustrate!
This is the reference diagram, I love how it shows the horse's balance gradually shift to the hind end as you move up the pyramid.
This is the pyramid using photos of horses who have been at Bit of Honey over the years. As expected, there were many Rhythm, Relaxation, and even Contact photos on my computer, since they are at the bottom of the pyramid most of our riding and training time is spent on those foundations. I was able to find a decent impulsion photo - you can tell because the horse is really reaching underneath herself with her hind legs and her haunches are significantly lower than her withers but she's definitely moving forwards so has the "thrust" required of impulsion.
Straightness had to be a halt photo - apparently we don't save enough pictures of horses coming straight towards the camera or going straight away! Lastly the collection photo had to be of a horse placing all her weight in her hind end, loading the springs in her legs to take off over a jump. We don't spend a ton of time in true collection because it's the most physically taxing for the horse and it's more important to build the foundation before you place the top on the pyramid, but we definitely see true shifting of weight entirely to the hind end with good jumping form in the horse!