 nSides = 26
 nBCtypes = 12
 bclabel = {
    'wall_1_out',
    'wall_2_out',
    'wall_3_out',
    'wall_4_out',
    'wall_5_out',
    'wall_6_out',
    'wall_1_in',
    'wall_2_in',
    'wall_3_in',
    'wall_4_in',
    'wall_5_in',
    'wall_6_in' 
}
