use the up and down arrows to control the thickness and use the right and left arrow to control the direction of the ball.but if you want a nice pattern don't use it you can use it for changing the pattern if you press either one then press c Use h to hide the ball and s to show it.c clears the screen.You can also press space to stop the ball and you can drag it even without pressing the see inside button.Use the green flag for it to start or start again if you pressed space.Press see inside to change the speed.