animation in applets

i have created an applet that draws 4 circles of the same size and now im trying to get the circles to move in single steps in a square motion using clearing them as they go along..and i want the loop to keep going say 5 times.any help or an different example or anything owuld be apprectiated! thankyou :)

Define an abstract Path interface that allows you to reset the path, and return a position on the path given a "time" variable. Implement the Path interface in a SquarePath class.