Let ABC be a triangle, D be any point on the plane. AD,BD,CD meet (ABC) again at A1,B1,C1. H is on BD such that HA perpendicular with AB. Ab is circumcenter of circle (AB1H). Define Ab,Ac,Ba,Bc,Ca,Cb cyclically. Then six points AbCbCaBaBcAc are the hexagon circumscribed. I named the result is Viet Nam hexagon
