triangular mesh

hole = [
    (2,2)
    (4,2)
    (4,4)
    (2,4)
]

boundary = [
    (0,0)
    (10,0)
    (10,10)
    (0,10)
]

hole = [
    (6,6)
    (8,6)
    (8,8)
    (6,8)
]

end