 The church is designed in late Byzantine cross @-@ in @-@ square style . It was constructed from stones and brickwork , a construction technique known as opus <unk> , and measures 16 by 6 @.@ 90 metres ( 52 @.@ 5 ft × 22 @.@ 6 ft ) , 16 by 6 @.@ 70 metres ( 52 @.@ 5 ft × 22 @.@ 0 ft ) , or 14 @.@ 20 by 4 @.@ 80 metres ( 46 @.@ 6 ft × 15 @.@ 7 ft ) , depending on the source . The walls of the church are 0 @.@ 80 metres ( 2 @.@ 6 ft ) thick . The colour of the bricks gives the church a <unk> appearance . 
