def stepper(d):
conf=d["stepper"]
conf["back_x"]=conf["front_x"]-conf["length"]
conf["top_y"]=conf["center_line_y"]-conf["width"]/2
r=rect(conf["back_x"],conf["top_y"],conf["length"],conf["width"])
r.set_style(Styles.get_construction_style(d))
return r
