background(255)
line(10, 0, 10, height())
line(width(), 10, 0, 10)
background(255)
for i in range(0, int(height()), 10):
line(0, i, width(), i)
for i in range(0, int(width()), 10):
line(i, 0, i, height())
def draw():
background(255)
for i in range(0, int(height()), 10):
line(0, i, width(), i)
for i in range(0, int(width()), 10):
line(i, 0, i, height())
timer(draw)