The difference between straight hook and curved hook

I think vertical hook and curved hook are two different strokes in calligraphy.

Vertical hook is a hook from top to bottom, shaped like an inverted hook. When writing, you need to lift the nib first, then hook it down quickly, and finally pull the nib back to its original position.

Hooks are hooks from left to right, shaped like hooks. When writing, you should first tilt to the lower right corner, then pause at the nib, and finally pull the nib back quickly.