Drawing With A Single Line

My drawing style is usually cartoonish and constrained. I'm trying to break out of that, and one way I do that is to sketch while keeping the pen on the paper and not take it off. I like how it ends up. The content is still recognizably mine (to me anyway) but I like trying to break out of my normally-constrained style. Here are two recent sketches. The majority of them are made without lifting the pen, and then some final decoration is done relaxing this constraint.