GRAPHREP
SET x_param:1cm
SET y_param:1cm

FILL color:darkblue
POLYGON 3 x1:0 y1:0
          x2:(x_param) y2:(-1.5*y_param)
          x3:(2*x_param) y3:0
FILL color:blue
POLYGON 3 x1:(2.3*x_param) y1:(-0.5*y_param)
          x2:(x_param) y2:(-1.5*y_param)
          x3:(2*x_param) y3:0cm