step 1
draw the image (quite clear i guess^^)


step 2
press strg+k to get to the resizing tool. now make the image smaller, but let the horizontal and the vertical size on the same %.

tip: the smaller you make the pic, the more it's blurred.

step 3
resize the pic to its original size (if you resized it to 50%, make it 200% now etc) and you are done

do the same things like when you are blurring, just make the pic bigger at first and then make it small again.