After playing with canvas for some time I gave a birth to this small piece of… code. If you don’t have any idea what it is I’ll give you a hint. It’s a gradually appearing target created with the help of HTML5 canvas element. 5 elements actually.
The idea is simple: create several canvas elements with different radius values and absolutely position them at the same point. Step by step drawing is archived by repeatedly calling a drawCircle function with different values of radius property until it reaches Math.PI * 2.