A symmetrical pattern is a pattern in which converging lines form an angle that somewhat resembles an acute angle. When two patterns are symmetrical, one becomes exactly like another when flipped or turned, according to Primary Resources.
A common example of symmetry is a reflection. The image of an object looks exactly like the object when turned through an angle of 180 degrees. In geometry, some shapes have lines of symmetry. Such a shape is symmetrical because, when folded along that line of symmetry, it gives two equal halves that look exactly the same. Symmetrical patterns are evident among regular objects, or objects with proportional form.