Ball point pen stuff.
Sitting in the doc's office, waiting for a friend (to drive him home), and reading William Silvers' (of Disney fame) new book on acrylic painting... I got out the blue pen and doodled:
Reading V for Vendetta, and thought I'd practice on a few of the characters:
Not so good....My portrait sketching often looks like caricaturing, with too-big eyes, etc...:
Overall, blue ballpoint pen sketching is convenient and a good exercise. You can't erase.