Tessellations divide space by algorithms.

Lines ("edges") in Voronoi ("V") divide space into regions closest to each point.

Delaunay ("D") connects the points into triangles whose circles contain no other point; the circles' centers are Voronoi's vertices.

Centroidal-Delaunay ("C") places vertices at mass centers of Delaunay triangles.

Gabriel ("G") removes a Delaunay edge if the circle formed along two of D's points contains another point.

Curious? Check it out in 2D.