Am making a drawing machine for a thesis. I want it to make vaguely round blob polygons. No bezier curves - I want to use a polygon detection algorithm. I've got a method worked out of turning round slowly and then cutting off. Exterior angles should add up to TWO_PI, that's when we stop turning.

Problem is, the line sometimes over shoots the start or turns in to quickly. Instead of a nice wobbly blob it has a nasty kink in it. I thought of cutting it off if it gets too close to the start but that'd just not nice enough.

Any suggestions?
Code:

Tracer test;
void setup(){
size(400,400);
test = new Tracer();
}
void draw(){
test.draw();
}
void mousePressed(){
test.trace(mouseX,mouseY);
}
class Tracer{
  Polygon [] polys;
  boolean write;
  float theta,radian;
  Tracer(){
    polys = new Polygon[1];
    polys[0] = new Polygon(random(width),random(height));
  }
  void trace(float x, float y){
    float theta = random(TWO_PI);
    float circum = TWO_PI-0.5;
    float xStart = x;
    float yStart = y;
    boolean write = true;
    int num;
    if (polys.length < 2)
	num = 0;
    else{
	newPolygon(polys[polys.length-1]);
	num = polys.length-1;
    }
    polys[num] = new Polygon(x,y);
    float turn = 0.0;
    
    while(turn < circum){
	x += cos(theta+turn)*random(4,8);
	y += sin(theta+turn)*random(4,8);
	polys[num].addVertex(x,y);
	turn += random(0.4);
	if(turn > PI && dist(x,y,xStart,yStart) < 10) break;
    }
  }
  void draw(){
    for(int i = 0; i < polys.length; i++){
	polys[i].draw();
    }
  }
  void newPolygon(Polygon newPolys) {  
    Polygon [] temp = new Polygon[polys.length + 1];  
    System.arraycopy(polys, 0, temp, 0, polys.length);  
    temp[polys.length] = newPolys;   
    polys = temp;
  }
}
class Polygon{
  float [] x,y;
  Polygon (float [] points){
    x = new float[points.length/2];
    y = new float[points.length/2];
    for(int i = 0; i < points.length; i+=2){
	x[i/2] = points[i];
	y[i/2] = points[i+1];
    }
  }
  Polygon (float startX, float startY){
    x = new float[1];
    y = new float[1];
    x[0] = startX;
    y[0] = startY;
  }
  void addVertex(float addX, float addY){
    x = append(x, addX);
    y = append(y, addY);
  }
  void draw(){
    beginShape(POLYGON);
    for(int i = 0; i < x.length; i++)
	vertex(x[i],y[i]);
    endShape();
  }
}