Left and right profiles of the same model skull, sketched on two consecutive evenings using a thick white pen for initial lines, then dilute grey ink to add form/shadows, and water-colour for background. This skull’s been a favourite and familiar subject since I started sketching (see below for earlier attempts over the years), I bought it for £1 at a flea market when I was about ten! It’s always a challenge to draw, the many ridges, curves and cavities are as rich and varied as a landscape, and it’s great for exploring shade and form. Here’s a similar model if you fancy having a similarly patient life/death model to sketch.
Kuretake white pen, dilute Lexington grey in detailer water-brush, water-colour, A5 – 30 mins
Mostly drawing 
I have been complaining about not having anything to draw and the weather being awful, but now I am inspired to set up some nice still lifes. Flea markets should be great places to pick up interesting objects, but such luck as yours I´m not expecting I will have, that skull is a heck of a find! And the drawings are great, of course. 🙂
Thanks Viktoria, happy hunting!