Captured Grids

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 020202020202020202020202020202020 0 0
0 02020202020202020202020202020_020 0 0
0 020202020 0 0 0 0 0 0 0 0 0202020 0 0
0 020202020 0 0 0 0 0 0 0 0 0202020 0 0

The “0” placed between “_” and “2” (_02) is surrounded by occupied grid cells only, it is “captured”.