Element #0
0: 0 1 3 4
Element #1
0: 1 2 4 5
Element #2
0: 3 4 6 7
Element #3
0: 4 5 7 8
========= Face restriction; marker: 4 ========
num_elem: 2, elem_size: 2, num_dof:  9
0: 3 0
0: 6 3
========= Face restriction; marker: 2 ========
num_elem: 2, elem_size: 2, num_dof:  9
0: 2 5
0: 5 8
========= Face restriction; marker: 1 ========
num_elem: 2, elem_size: 2, num_dof:  9
0: 0 1
0: 1 2
========= Face restriction; marker: 3 ========
num_elem: 2, elem_size: 2, num_dof:  9
0: 7 6
0: 8 7