I am trying to build a simple cube out of a set of a couple of points.

Each point of the 3D shape is defined by its x,y,z coordinates/variables. I want to be able to control the coordinates of each point separately - that is why I declared each x,y,and z coordinate...
At one point I want to be able to change the x coordinate of point5, while at another - I want to be able to change the z coordinate of point8 (for example)

When I run the sketch, however, only the four corner points are visible. Could you point out as to what I am missing or doing wrongly? Thank you in advance!

import processing.opengl.*;

PointsC point1, point2, point3, point4, point5, point6, point7, point8;
float rotX, rotY;

void setup() {
  size(500, 500, P3D);
  background(255);
  point1 = new PointsC(0, 0, 0);
  point2 = new PointsC(100, 0, 0);
  point3 = new PointsC(0,100,0);
  point4 = new PointsC(100, 100, 0);
  point5 = new PointsC(0, 0, -100);
  point6 = new PointsC(100, 0, -100);
  point7 = new PointsC(100, 100, -100);
  point8 = new PointsC(0, 100, -100);
}
void draw() {
  background(255);
  translations();
 
  point1.drawpoint();
  point2.drawpoint();
  point3.drawpoint();
  point4.drawpoint();
  point5.drawpoint();
  point6.drawpoint();
  point7.drawpoint();
  point8.drawpoint();

 
} //end draw

void mouseDragged() {

  float x1 = mouseX-pmouseX;
  float y1 = mouseY-pmouseY;
  rotX = (mouseY * -0.01);
  rotY = (mouseX * 0.01);
}
  void translations() { 
  translate(width/2, height/2);
  rotateX(rotX);
  rotateY(rotY);
}

 

class PointsC {
  float x1, y1, z1, x2, y2, z2, x3, y3, z3, x4, y4, z4, x5, y5, z5, x6, y6, z6, x7, y7, z7, x8, y8, z8;
  PointsC(float xpos, float ypos, float zpos) {
    x1 = xpos;
    x2 = xpos;
    x3 = xpos;
    x4 = xpos;
    x5 = xpos;
    x6 = xpos;
    x7 = xpos;
    x8 = xpos;
    y1 = ypos;
    y2 = ypos;
    y3 = ypos;
    y4 = ypos;
    y5 = ypos;
    y6 = ypos;
    y7 = ypos;
    y8 = ypos;
    z1 = zpos;
    z2 = zpos;
    z3 = zpos;
    z4 = zpos;
    z5 = zpos;
    z6 = zpos;
    z7 = zpos;
    z8 = zpos;
  }
    void drawpoint() {
      stroke(0);
      strokeWeight(5);
      point(x1,y1,z1);
      point(x2,y2,z2);
      point(x3,y3,z3);
      point(x4,y4,z4);
      point(x5,y5,z5);
      point(x6,y6,z6);
      point(x7,y7,z7);
      point(x8,y8,z8);
    }
  }