First of all, what you probably mean is the 'edge' of the visible universe since the universe can have no edge in space. Secondly, it is impossible for any telescope to see individual stars in galaxies farther away than a few hundred million light years or about 1/100 the distance to the 'edge' of the observable universe. As for 'square stars', I have never heard of such a thing, and believe me if such a thing had been found, the astronomical community would be abuzz. There are, however, many examples of stars that are not spherical. These stars are found in binary star systems in close contact with each other so that the enormous gravitational fields distort the stars into football shapes. Also, rapid rotation of individual stars can make them flattened in to ellipsoidal shapes.