following some drawing tutorials that I find on-line. Especially for inkscape I found some real good ones (see e.g. this). Here are the results of some days playing around with Inkscape or the GIMP. Some of the drawings have been printed on frisbee shirts, others never made it to become printed.
An example is the rotating brain in my research page. I build that in a week-end, after asking Marleen to make some 3d brain plots with Brain Voyager which I put into an animation. I then decided to add the magnifying glass that moves around randomly to create a cooler effect. I will soon add other examples.