// SignWave shaped hill

    Xamp  = 50; // one wave length
    Yamp  = 50; // one wave length
    Zamp  = 20; // amplitude (height)

    Xcount = 10;
    Ycount = 200;
    pitchX = Xamp/Xcount;
    pitchY = Yamp/Ycount;
    delta = pitchX;


    X2 = Xamp/2;
    Y2 = Yamp/2;
    D2 = delta/2;

// ---------------------------------------------------------------------
 module two_by_two ( amp, seqX, x_angle_pitch, pitchY, D2, x, y, Zamp, PitchX )
 {
    z = amp * cos((seqX      ) * x_angle_pitch - 180);
    g = amp * cos((seqX + 1  ) * x_angle_pitch - 180);
    hull() {
    translate([x        , y, Zamp]){     cube([delta, delta, z + Zamp + 0.1]);    }
    translate([x + delta, y, Zamp]){     cube([delta, delta, g + Zamp + 0.1]);    }
    }
}
// ---------------------------------------------------------------------
    module SignWaveHill(Xamp, Yamp, Zamp, delta) {
    pitchX = Xamp / Xcount;
    y_angle_pitch = 360/Ycount;
    x_angle_pitch = 360/Xcount;

	for (	 seqY = [0:pitchY/2:Ycount  - 1] ){
	    amp = Zamp * cos(seqY * y_angle_pitch - 180);

            for ( seqX = [0:0.5:Xcount - 1] ){

              x = (seqX   ) * pitchX ;
	      y = (seqY   ) * pitchY   - Y2;

     	     two_by_two ( amp, seqX, x_angle_pitch, pitchX, D2, x, y,  Zamp, pitchY );
	      y = (seqY + 0.5 )* pitchY  - Y2;
	     # two_by_two   ( amp, seqX, x_angle_pitch, pitchX, D2, x, y,  Zamp, pitchY );

	     }
	 }
        }	


  SignWaveHill(Xamp, Yamp, Zamp, pitchX);