MEKL Operation:

MSG simply makes a shell along a hole. After this, one might add vertices, edges, faces, loops. There must be loops, because the new hole penetrates at least one face.

MEKL makes an edge & at the same time kills a loop. A commonly utilized MEKL is adding an edge associating the outer loop and the inner loop of a face. In this, the number of edges E is enhanced by 1 and the number of loops L is reduced by 1 since that loop is killed. Figure (a) illustrated two loops of the top face while Figure (b) shows the new edge added after performing a MEKL. Therefore, the inner and outer are "joint" together with the new edge becoming a single face.

(a)                                            (b)

Figure: MEKL Operation