These three are quick, 5-10 minute drawings. A short drawing time forces you to simplify and reduce what you see into essentials.
The essence of something rather than the exact.
Sometimes it works, sometimes it doesn't.
And I very rarely get a 10 minute drawing anywhere near finished.
But a short drawing time does avoid over working a drawing. For example:
The model is 'well defined' (as the tutor says), but he doesn't look any where near as much like Schwarzenegger's body double as I've made out.
Maybe simple is best.