I've been testing a program called Artrage for a couple of days (After a tip from Torstan here on the site). It is a drawing program that let you use different tools like watercolour, oil paint, ink pens etc to make drawings. The program is really great and here is a very quick map of a small village I made while trying to learn the program. It really feels like it has a lot of potential, but most of all it is really fun to use.

