import matplotlib.pyplot as plt

def draw_fractal(ax, levels=4, x=0, y=0, size=1):
    if levels == 0:
        ax.add_patch(plt.Rectangle((x, y), size, size, color='navy'))
    else:
        size3 = size / 3
        for i in range(3):
            for j in range(3):
                if (i + j) % 2 == 0:
                    draw_fractal(ax, levels - 1, x + i * size3, y + j * size3, size3)

fig, ax = plt.subplots()
ax.set_aspect(1)
draw_fractal(ax)
plt.show()