Stable square emission patterns are observed in argon discharge at atmospheric pressure by using a dielectric barrier discharge device with different lateral boundary conditions. The spatio-temporal dynamics of square pattern in nanosecond time scale is investigated. It is found that the square pattern is an interlacing of two oscillating square sublattices, which have time sequence inversion behavior. The influence of the wall charge distribution on the forming process and the spatio-temporal dynamics of the emission patterns is discussed.