private static Cell BuildPartialCell(Triangle tri, Vector2Int pos, TriangleCells cellDir)
{
var cell = tri.CreateCell(pos);
tri.AddCell(cell, cellDir);
var newTri = tri;
do
{
cell.AddTris(newTri.GeoTri);
newTri = newTri.Right;
} while (newTri != tri);
return(cell);
}