Yul Guk is named after the neo Confucius scholar in the 16th century with 38 movements which marks the 38th parallel Yi I's birthplace.
It is the first form to date where slow movements are used to highlight the coordination of breathing with attacks and defenses.
This form also incorporates multiple angles of attack with a three part movement.
NB: Video credit to Chloe Orsag. Here the form is spliced to show the reverse half of the form.
There are many ways to practice forms. They can be done in cardinal order(1, 2, 3 etc) or reverse order (...3,2,1), or at random. They can be done slowly to aid memorizing the movements, or at street speed to emphasize the fight choreographed into each form. They can even be done inside your head, imagining the class room dojang; try it it's harder than it sounds.
It's also interesting to note that doing the forms for the instructor in class is very different from teaching the form to someone. Ask yourself, what changes? The form is the same. The class is the same. But roles are reversed. We develop new neural pathways to deal with the same movements.