float fi=0;
float x,y,z,r;
int i,j,k;

int NSEGMENTS=3000;
int N=40;
int M=18;


void setup() 
{
  size(400, 400, P3D);
  colorMode(RGB,100);
}


void DrawKnot()
{
  int i;
  float x,y,z,xl,yl,zl;
  float beta;
  float phi,theta;
  float r;
  float mx=(mouseX<=0?50:mouseX);
  float my=(mouseY<=0?200:mouseY)/100.0f;
  float distance=dist(200,200,mx,my);
 
  zl=yl=xl=-255;
  beginShape(LINES);
  for (i=0;i<=NSEGMENTS;i++) {

    
    beta = mx*i * PI / (float)NSEGMENTS;
    r = 1.2 * 0.6 * sin(0.5 * PI + 6 * beta);
    theta = 4 * beta*my;
    phi = 0.2 * PI * sin(6 * beta);
    x =  r * cos(phi) * cos(theta);
    y =  r * cos(phi) * sin(theta);
    z =  r * sin(phi);

    stroke(0,beta*r,100,20);
       if (zl==-255) {
         xl=x;
         yl=y;
         zl=z;
       }
       vertex(xl,yl,zl);
       vertex(x,y,z);       

       xl=x;
       yl=y;
       zl=z;
   }
   endShape();
}


void draw() 
{
  background(0,0,0);
  translate(200,200);
  scale(300,300,300);
  DrawKnot();
}