use "robot"

pause = 5
xstep = 50 ystep = 5
startx = 50
starty = 400 + ystep / 2

for (y = 0, y < 300, y = y + ystep) {

    mouseMove(startx, (starty+y))
    mousePress(BUTTON1)
    for (i = 0, i < 600, i = i + xstep) {
        mouseMove((startx+i), (starty+y))
        delay(pause)
    }
    mouseRelease(BUTTON1)
    delay (pause*3)
	
}