I wanted to make a drawing app that has a bit more sloppy drawing style than most of the drawing apps/programs we're familiar with.
Fast brushstrokes will result in a thinner line than slower strokes, and you can adjust various settings (like width or splatter amount) at the bottom. Clicking on the big paint bucket will bring out an extended palette.
The eraser is different in texture, in that the width is fixed, but it can be adjusted with the slider below just like the regular brush.
So, have fun