---

SQUARE_SIZE = 40
ROWS = 10
COLS = 10

penup()
setposition(-200, -200)

for row in range(ROWS):
    for col in range(COLS):
        if (row + col) % 2 == 0:
            color_value = Color.red
        else:
            color_value = Color.black
        
        color(color_value)
        
        begin_fill()
        for i in range(4):
            forward(SQUARE_SIZE)
            left(90)
        end_fill()
        
        forward(SQUARE_SIZE)

    backward(SQUARE_SIZE * COLS)
    left(90)
    forward(SQUARE_SIZE)
    right(90)