color backgroundColor;
  color foregroundColor;
  color foregroundColor2;
  
  float px, py;
  float pfx, pfy;
  float pv2, pvx, pvy;
  float pa2, pax, pay;
  float pMass, pDrag;
  
  void setup() {
    size(640, 360, P3D);
    noStroke();
    backgroundColor = color(134, 144, 154);
    foregroundColor = color(235, 235, 30);
    foregroundColor2 = color(240, 130, 20);
    initParticle(0.6, 0.9,  width/2, height/2);
  }
  
  void draw() {
    background(backgroundColor);
    pushMatrix();
  
    iterateParticle(0.15*(-px+mouseX), 0.15*(-py+(height-mouseY)));
  
    translate(width/2, height/2, 0);
    fill(foregroundColor);
    drawK();
   
    pushMatrix();
    translate(0, 0, 1);
    translate(0.75 * (px-width/2), -0.75 * (py-height/2), 0);
    translate(0.75 * (px-width/2), -0.75 * (py-height/2), 0);
    rotateZ(atan2(-(py-height/2), (px-width/2)) + PI/2);
    rotateX(PI);
    rotateZ(-(atan2(-(py-height/2), (px-width/2)) + PI/2));
    
    fill(foregroundColor2);
    drawK();
    popMatrix();
  
    translate(0.75 * (px-width/2), -0.75 * (py-height/2), 2);
    rotateZ(atan2(-(py-height/2), (px-width/2)) + PI/2);
    
    fill(backgroundColor);
    beginShape(QUADS);
    vertex(-640, 0);
    vertex( 640, 0);
    vertex( 640, -360);
    vertex(-640, -360);
    endShape();
    
    popMatrix();
   
  }
  
  void initParticle(float _mass, float _drag, float ox, float oy) {
    px = ox;
    py = oy;
    pv2 = 0.0;
    pvx = 0.0;
    pvy = 0.0;
    pa2 = 0.0;
    pax = 0.0;
    pay = 0.0;
    pMass = _mass;
    pDrag = _drag;
  }
  
  void iterateParticle(float fkx, float fky) {
    // iterate for a single force acting on the particle
    pfx = fkx;
    pfy = fky;
    pa2 = pfx*pfx + pfy*pfy;
    if (pa2 < 0.0000001) {
      return;
    }
    pax = pfx/pMass;
    pay = pfy/pMass;
    pvx += pax;
    pvy += pay;
    pv2 = pvx*pvx + pvy*pvy;
    if (pv2 < 0.0000001) {
      return;
    }
    pvx *= (1.0 - pDrag);
    pvy *= (1.0 - pDrag);
    px += pvx;
    py += pvy;
  }
  
  void drawK() {
    pushMatrix();
    
    scale(1.5);
    translate(-63, 71);
    beginShape(QUADS);
    vertex(0, 0, 0);
    vertex(0, -142.7979, 0);
    vertex(37.1992, -142.7979, 0);
    vertex(37.1992, 0, 0);
    
    vertex(37.1992, -87.9990, 0);
    vertex(84.1987, -142.7979, 0);
    vertex(130.3979, -142.7979, 0);
    vertex(37.1992, -43.999, 0);
  
    vertex(77.5986-.2, -86.5986-.3, 0);
    vertex(136.998, 0, 0);
    vertex(90.7988, 0, 0);
    vertex(52.3994-.2, -59.999-.3, 0);
    endShape();
    //translate(63, -71);
    popMatrix();
  }