float MID;

void keyPressed() { if(key == ' ') reset();}
void reset(){
//  lines = new ArrayList<Line>();
  background(255);
  line(MID,0,MID,height);
  currentLine = null;
  spinningLine = null;
}

//ArrayList<Line> lines = new ArrayList<Line>();
void setup(){
   size(500,500); 
  MID = 250;
   stroke(0,20);
   reset();
}
Line currentLine;
Line spinningLine;
void mousePressed(){
  currentLine = new Line(mouseX,mouseY);
spinningLine = null;
}
void mouseDragged(){
  currentLine.addPoint(mouseX,mouseY);
}

void mouseReleased(){
  if(currentLine == null) return;
  // lines.add(currentLine); 
   spinningLine = currentLine;
  currentLine = null;  
}
void draw(){
  if(currentLine != null) currentLine.draw();
  if(spinningLine != null) {
    spinningLine.move();
   spinningLine.draw();
  } 
   /*for(Line n : lines){
      n.move();
      n.draw();
   } */
}

class Line {
  Point start;
  float a = -PI;
  ArrayList<Point> tail = new ArrayList<Point>();
   Line(float px, float py){
      start = new Point(px,py);
   } 
   void addPoint(float x, float y){
      tail.add(new Point(x,y)); 
   }
   void move(){
     a += PI/64;
   }
   void adjust(Point p){
      if(p.x > width / 2) p.xs-= 1; 
      if(p.x < width / 2) p.xs+= 1; 
      p.x += p.xs;
   }
   void draw(){
      Point last = reangle(start);
     for(Point p : tail){
         Point current = reangle(p);
        line(last.x,last.y,current.x,current.y);
        last = current;
     } 
   }
  Point reangle(Point p){
     Point newPoint = new Point( 250 +(   (250 - p.x) * cos(a)),p.y);

     return newPoint;
  }
}

class Point{
  float x,y,xs,ys;
   Point(float px, float py){
      x = px;
      y = py;
   } 
}