// upper version 
// VERSION = 2022-11-01 22:06"
module slope (L, H, W, D) {

  translate([ -W/2, -D * 2 , 0])   cube([ W, D, H]);
  translate([ -W/2,  D  + L, 0])   cube([ W, D, H]);

  polyhedron(
      points = [
      	     [ -W/2,  0 , 0],
             [  W/2,  0 , 0],
             [  W/2,  L , H], 
             [ -W/2,  L , H], 
	               
             [ -W/2,  L , 0], 
             [  W/2,  L , 0], 
	     ],
      faces  = [
      	     [ 0, 1, 2, 3],
	     [ 3, 2, 5, 4],
             [ 4, 5, 1, 0],
             [ 0, 3, 4],
             [ 1, 5, 2]
	     ]
	     );
}
 rotate([0, 180, 0])  //  for lower, invert

//      Length   Height     Width Delta
slope (1000,     250,       300, 100);  // 1 x 0.3 m/m for default setup