The central theme of this low-relief is two circle motifs on the platform side walls which look just like a triumphal arch (“Isjtar” is the goddess who gave her name to one of the gates of Babylon under the rule of Nabuchodonosor). Here the opposition is between open circles and squares and closed circles and squares in two tones. The five elements on the tympanum and the two panels on the side walls form a synthesis of Gilbert Decock’s works, which use a language full of imagery. Decock describes the development of the five part frieze as follows: “The square comes from the bottom left behind the open circles; it appears image after image, until it becomes a closed head motif on the right. This progressive movement towards the foreground offers the continuity of a cartoon. This regularity is however (consciously) interrupted by the strongly emphasised open window.”