def snail(snail_map):
    result = []
    if not snail_map or not snail_map[0]:
        return result

    while snail_map:
        result += snail_map.pop(0)

        if snail_map and snail_map[0]:
            for row in snail_map:
                result.append(row.pop())

        if snail_map:
            result += snail_map.pop()[::-1]

        if snail_map and snail_map[0]:
            for row in reversed(snail_map):
                result.append(row.pop(0))

    return result


# https://www.codewars.com/kata/521c2db8ddc89b9b7a0000c1/train/python
# ich kam nicht selbstständig auf diese lösung. Könntes du mir diese erklären? ich dachte pop löscht.