The shape of an existing array can be modified as long as the new shape is compatible with the existing shape. That is, the number of elements of the new shape must be the same as the number of elements of the existing shape.

At this point, let me also introduce the function range() which creates a one-dimensioned array with integer values starting at a specified value and incrementing by one each time until a specified ending value is reached (ending value not included in the range). We will then reshape the array into a two-dimensioned array.

a = range(1, 13)
print a
[1 2 3 4 5 6 7 8 9 10 11 12]
b = reshape(a, (3,4))
print b
[[1  2  3  4]
 [5  6  7  8]
 [9 10 11 12]]
x = range(1, 25)
y = reshape(x, (2, 3, 4))
print y
[[[ 1  2  3  4]
  [ 5  6  7  8]
  [ 9 10 11 12]]

 [[13 14 15 16]
  [17 18 19 20]
  [21 22 23 24]]]