import numpy as np

def triang():
    # Vertices of the triangulation
    N = np.zeros([4, 2])
    N[0][:] = [0.0, 0.0]
    N[1][:] = [1.0, 0.0]
    N[2][:] = [1.0, 1.0]
    N[3][:] = [0.0, 1.0]

    # Triangles
    T = np.zeros([2, 3])
    T[0] = [0, 1, 2]
    T[1] = [0, 2, 3]

    # Numbers for the nodes defining Dirichlet Edges
    Db = np.zeros([1, 2])
    Db[0][:] = [0, 1]

    # Numbers for the nodes defining Neumann Edges
    Nb = np.zeros([3, 2])
    Nb[0][:] = [1, 2]
    Nb[1][:] = [2, 3]
    Nb[0][:] = [3, 0]

    return (N, T, Db, Nb)