constructor(line_min = 10, line_max = 100) {

    let p1 = createVector(0, 0, 0);

    let p2 = createVector(random(line_min,line_max), 0, 0)

    let p3 = createVector(random(p2.x), random(line_min, line_max), 0)

    let p4 = createVector(p3.x, random(p3.y), random(line_min, line_max))

    let centroid = createVector((p1.x+p2.x+p3.x+p4.x)/4, 

                                (p1.y+p2.y+p3.y+p4.y)/4,

                                (p1.z+p2.z+p3.z+p4.z)/4) 

    p1 = p1.sub(centroid)

    p2 = p2.sub(centroid)

    p3 = p3.sub(centroid)

    p4 = p4.sub(centroid)

    this.p1 = p1

    this.p2 = p2

    this.p3 = p3

    this.p4 = p4

    this.face1 = [ p2, p3, p4, this.fnorm(p2, p3, p4) ]

    this.face2 = [ p1, p4, p3, this.fnorm(p1, p4, p3) ]

    this.face3 = [ p1, p2, p4, this.fnorm(p1, p2, p4) ]

    this.face4 = [ p1, p3, p2, this.fnorm(p1, p3, p2) ]

    this.spin_x = random(-0.008, 0.008)

    this.spin_y = random(-0.008, 0.008)

  }  

​

  fnorm(p1, p2, p3) {

    let a = p5.Vector.sub(p2,p1)

    let b = p5.Vector.sub(p3,p2)

    let n = p5.Vector.cross(a, b)

    let s = (n.dot(p1) > 0 ? 1 : -1)

    return n.mult(s)

  }

​

  drawFace(f) {

    beginShape()

    normal(f[3].x, f[3].y, f[3].z)

    vertex(f[0].x, f[0].y, f[0].z)

    vertex(f[1].x, f[1].y, f[1].z)

    vertex(f[2].x, f[2].y, f[2].z)

    endShape(CLOSE)

  }

  draw() {

    push()

    rotateX(frameCount * this.spin_x)

    rotateY(frameCount * this.spin_y)

    this.drawFace(this.face1)

    this.drawFace(this.face2)

    this.drawFace(this.face3)

    this.drawFace(this.face4)

    pop()

  }

}

​

​