simple sorting figure the bubblesort applet with bars figure the partly sorted bars if you started sort with run and the arrows are whizzing aroundyou can freeze the process at any point by pressing the step button you can then single-step to watch the details of the operation or press run again to return to high-speed mode the draw button sometimes while running the sorting algorithm at full speedthe computer takes time off to perform some other task this can result in some bars not being drawn if this happensyou can press the draw button to redraw all the bars doing so pauses the runso you'll need to press the run button again to continue