beginShape() and endShape() test

size(500, 100, P3D);
background(200);
box(10);
beginShape();
vertex(30, 20);
vertex(85, 20);
vertex(85, 75);
vertex(30, 75);
endShape();

beginShape();
vertex(130, 20);
vertex(185, 20);
vertex(185, 75);
//vertex(130, 75);
endShape();

beginShape();
vertex(230, 20);
vertex(285, 20);
//vertex(285, 75);
//vertex(230, 75);
endShape();

beginShape();
vertex(330, 20);
//vertex(385, 20);
//vertex(385, 75);
//vertex(330, 75);
endShape();