A maltitude ("midpoint altitude") is a perpendicular drawn to a side of a quadrilateral from the midpoint 
of the opposite side.
If the quadrilateral is cyclic, then the maltitudes are concurrent in a point 
known as the anticenter. Amazingly,
in addition, the centroid 
of the quadrilateral vertices is exactly the midpoint of the line connecting 
and the quadrilateral's circumcenter 
.
