This is defined to be a line from the middle of one side of the triangle t = (ABC), F middle of BC say, to a point I dividing the perimeter in two equal parts: here |FB|+|BI| = |IA|+|AC|. The following is true: (1) FI is parallel to the bisector AH of angle A. (2) The line IG, orthogonal to AB at the "cleaver point" I, passes through the middle G of the arc BAC of the circumcircle of triangle t. (3) The three cleaver-lines, corresponding to the middles of the three different sides intersect at a point K. (4) K is the incenter of the medial triangle s, whose vertices are the middles of the sides of t.
References
[HonsEpis] Honsberger, R. Episodes in Nineteenth and Twentieth Century Euclidean Geometry. Washington DC, Math. Assoc. Ammer., 1995, p. 1.