[Tutor] Nested list item assignment

[Tore Ericsson]

Can anybody explain line 6 in this:

>>> A = [[0]*3]*3
>>> A
[[0, 0, 0], [0, 0, 0], [0, 0, 0]]
>>> A[0][0] = 1
>>> A
[[1, 0, 0], [1, 0, 0], [1, 0, 0]]
>>> # One assigned, three updated!? 
>>>

Thanks / Tore