import numpy as np

# Generate a 2D array
a = np.array([[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]])

# Transpose the 2D array
a_transpose = np.transpose(a)
print("Original 2D array: \n", a)
print("Transposed 2D array: \n", a_transpose)