Sure, none of these sketches have anything on Van Goh, but you said you drew these in only five minutes?!?!?! (I hope that means five minutes per sketch, not five minutes total. If you drew those in five minutes altogether, I'll really feel bad about myself.) Anyways, my favorite was probably the first one. Even though the proportions aren't perfect, is has a lot of great detail. Keep drawing!
These are really good. The only thing I'm gonna say overall is that the drawings would look more realistic if they werent so harshly outlined. That tends to make them look flat. Usualy the borders of objects are defined by shadows not lines.
But for five-minute-doodles great job! Keep posting.
When you want something, the whole universe conspires to make it happen.
-- Ralph Waldo Emerson.