output list reducing each time through loop

[3Pinter]

Hey Buran,

Super interesting article and it explained a lot to me. However I don't get a tiny thing: lists are mutable, okay. And therefor doing this:

start = [1,2,3,4,5]
new = []
t = True
for s in start:
    new.append(start)
    if t:
    	start.pop(0)
        t = False
print(new)

"new" will output [2,3,4,5] a few times. As expected.

But since lists are mutable I would expect that changing "start" to a new definition would alter the "new" list as well.

start = [1,2,3,4,5]
new = []
t = True
for s in start:
    new.append(start)
    if t:
    	start.pop(0)
        t = False
start = ["test"]
print(new)

But python will still output [2,3,4,5] a few times.

Why doesn't it output "test" a few times?