Python3: rotate a pandas 2d array slice by slice

I have an (20x4) ndarray and i need to rotate every 4 rows from beginning to form a new ndarray which has size of (5x16). For simplicity, here is a sample of the original data and the intended resulting data with random contents just to infer the way of transpose:

original ndaaray:

  0  1  2  3

0 x0 x1 x2 x3

1 x0 x1 x2 x3

2 x0 x1 x2 x3

3 x0 x1 x2 x3

4 z0 z1 z2 z3

5 z0 z1 z2 z3

6 z0 z1 z2 z3

7 z0 z1 z2 z3

8 c0 cm1 c2 c3

9 c0 c1 c2 c3

10 c0 c1 c2 c3

11 c0 c1 c2 c3

12 a0 a1 a2 a3

13 a0 a1 a2 a3

14 a0 a1 a2 a3

15 a0 a1 a2 a3

16 b0 b1 b2 b3

17 b0 b1 b2 b3

18 b0 b1 b2 b3

19 b0 b1 b2 b3

intended ndaaray:

  0  1  2  3  4  5  6  7  8  9  10 11 12 13 14 15

0 x0 x0 x0 x0 x1 x1 x1 x1 x2 x2 x2 x2 x3 x3 x3 x3

1 c0 c0 c0 c0 c1 c1 c1 c1 c2 c2 c2 c2 c3 c3 c3 c3

2 a0 a0 a0 a0 a1 a1 a1 a1 a2 a2 a2 a2 a3 a3 a3 a3

3 b0 b0 b0 b0 b1 b1 b1 b1 b2 b2 b2 b2 b3 b3 b3 b3

any suggestions?

What I have tried:

for i in range(0, 20):
df1.loc[i] = df2.loc[0:5, :].transpose().to_numpy()