Click flag two times to start. Move mouse around to draw. Space to erase all. Up-arrow to increase pen size. Down-arrow to decrease pen size. Right-arrow pen up. Left-arrow pen down. I recommend pressing the flag and then the right arrow key immediately. Then go to the point you want to start at and then press left-arrow key. Have fun! What will you create?
All code by me! @ZebraN8 Try pressing the up-arrow till the pen covers the screen then decrease to small size.