Here is a Demo I have been workin' on for a while(the one Game A gogo got insped by to make Pic A Gogo )
(one has been resized to 800x600)
and here are a few tips: when you select the pencil right click to draw a perfectly straight line, left click to draw free hand, when you select the square use the left mouse button to draw a square depending on xmouse and ymouse positions, when you select the odd thing that looks like a blue pencil use the left mouse button to draw a rainbow, when selecting the eraser click the right mouse button to fill in the canvas with the selected color, left mouse button erases or you can adjust the opacity on any of the selection to max so you can erase with that shape, In the full version I will have triangle drawing and circle drawing and a bunch of other cool stuff, the pictures (Screenshots) were all made with this "Game"
Hope you enjoy!