It is easy and common to offer a blank page, but we seem to prefer a set of markings to organize our work. Sometimes, the markings serve a general purpose of alignment and coordinates. Other times, the forms are specific to the task. And sometimes, they are just whimsical.
It’s always amazing to me the vast variety of different page rulings. There are more than a few here I’ve never seen in my travels. Conversely. there were many that came to mind not mentioned.