float x, y;
float lastX, lastY;
float branchLength;
float angle;
float minusAngle;
int step;
PVector vector;

Trunk left, right;

Trunk(float x, float y, float branchLength, float angle, float
minusAngle, int step) {

PVector vec = new PVector(0, -branchLength);
vec.rotate(angle);
lastX = x + vector.x;
lastY = y + vector.y;

if (step > 0) {
    left = new Trunk(last, lastY, branchLength * .75, angle -
minusAngle,
diffAngle, step - 1);
    right = new Trunk(lastX, lastY, branchLength * .75, angle +
minusAngle, diffAngle, step - 1);
  }
}

void drawMe() {
  stroke(0, 70);
  strokeWeight(4);
  if ( right != null)
    right.drawMe();
  if (left != null)
    left.drawMe();

  pushMatrix();
  translate(x, y);
  rotate(angle);
  noFill();
  pushStyle();
  fill(c);

  popStyle();
  popMatrix();
}