Exercises on iterators.sagews

for x in range(4):
    for y in range(4):
        print (x, y)

it = iter(range(4))
for x in it:
    for y in it:
        print (x,y)

L = range(4)
it1 = iter(L)
it2 = iter(L)
for x in it1:
    for y in it2:
        print (x,y)

L = range(4)
it1 = iter(L)
it2 = iter(L)
for x in list(it1):
    for y in list(it2):
        print (x,y)

L = range(4)
for x in list(iter(L)):
    for y in list(iter(L)):
        print (x,y)