triangle, parallelograms, incidence --- hints
Use the following steps to construct a figure.
1) Pick non-collinear points A, B, C [these can be moved]
2) Pick point M inside triangle A.B.C [point M can be moved]
3) Locate point M_c such that quadrilateral A.M.B.M_c is a parallelogram.
4) Locate point M_b such that quadrilateral A.M.C.M_b is a parallelogram.
5) Locate point M_a such that quadrilateral B.M.C.M_a is a parallelogram.