I have a 2d-matrix and I want to split it using a checkerboard pattern. example:
1,  2,  3,  4
5,  6,  7,  8
9, 10, 11, 12

into
1,  3,
5,  7,
9, 11,

and
2,   4
6,   8
10, 12

this should be: a = x[:, :, 0::2, :] and b = x[:, :, 1::2, :]
but now if I have a and b, how can I revert the transformation?