checker.py

size=512
print(f'''<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" width="{size//2}" height="{size//2}" viewBox="0 0 {size} {size}">
<rect width="{size}" height="{size}"/>
<path d="M0,0''')
for i in range(size//2):
    print(f'V{size}h1V0zm2 0')
print('M0,0')
for i in range(size//2):
    print(f'H{size}v1H0zm0 2')
print('" fill="#fff" fill-rule="evenodd" /></svg>')

checker.svg

mapnik.png