SAND_NUMBER = 10 sand = [Sand.random(9e-1, 11e-1) for i in range(SAND_NUMBER)] window = Window() plane = Plane(offset=[window.w/2, window.h/2], zoom=min(window.size)/10) angle = 0 while window.open: window.check() window.clear(mycolors.WHITE) angle += 0.01 angle %= 2*math.pi xoffset = math.cos(angle) yoffset = math.sin(angle) for grain in sand: x, y = plane.getToScreen(grain.center) x += xoffset*plane.zoom y -= yoffset*plane.zoom grain_pixel = Sand([int(x), int(y)], radius=grain.radius*plane.zoom) grain_pixel.show(window) window.flip()