Problem with append list in loop

[michaelko03]

Here is my code

import math
import numpy as np

z = 0
y= []
x = []

while z < 5:
    z = z + 1
    t = 0
    x.append([y])
    while t < 8:
        A = 10 + t
        y.append(A)
        t = t + z
print (x)

I want to separate the result of y list in each cycle from the second while loop 

I expect the result will be 
[10,11,12,13,14,15,16,17],
[10,12,14,16],[10,13,16],
[10,14],
[10,15]
[10,16]

but the outcome is 
[10,11,12,13,14,15,16,17,10,12,14,16,10,13,16,10,14,10,15,10,16
[10,11,12,13,14,15,16,17,10,12,14,16,10,13,16,10,14,10,15,10,16],
[10,11,12,13,14,15,16,17,10,12,14,16,10,13,16,10,14,10,15,10,16],
[10,11,12,13,14,15,16,17,10,12,14,16,10,13,16,10,14,10,15,10,16],
[10,11,12,13,14,15,16,17,10,12,14,16,10,13,16,10,14,10,15,10,16]

can anyone help me? Thank you