size(400, 400, P3D);
noStroke();
background(0);
pointLight(150, 250, 150, 40, 120, 200);
beginShape();
normal(0, 0, 4);
vertex(80, 80, -40);
vertex(320, 80, 40);
vertex(320, 320, -40);
vertex(80, 320, 40);
endShape(CLOSE);