printing points based on 4 - way symmetry
System . out . println ( df . format ( ( x + xc ) ) + " , ▁ " + df . format ( ( y + yc ) ) ) ; System . out . println ( df . format ( ( - x + xc ) ) + " , ▁ " + df . format ( ( y + yc ) ) ) ; System . out . println ( df . format ( ( x + xc ) ) + " , ▁ " + df . format ( ( - y + yc ) ) ) ; System . out . println ( df . format ( ( - x + xc ) ) + " , ▁ " + df . format ( ( - y + yc ) ) ) ;