lst = [
    ['a','b','c','d'],
    ['e','f','g','h'],
    ['i','j','k','l'],
    ['m','n','o','p'],
]

for x, ligne in enumerate(lst):
    print(x,ligne)
    for y, val in enumerate(ligne):
        print(x,y,val)

# Résultat
# 0 ['a', 'b', 'c', 'd']
# 0 0 a
# 0 1 b
# 0 2 c
# 0 3 d etc.