Draws a random soft shape with curveVertex().

SoftShape.pde

// See also:
// https://forum.processing.org/one/topic/how-to-create-a-closed-spline-curve.html

float[] radiusArray;

void setup() {
  size(600, 600);
  noLoop();
  noStroke();
  fill(32);

  final int resolution = 30;
  radiusArray = new float[resolution];
  
  for (int i = 0; i < resolution; i++) {
    radiusArray[i] = random(100, 120);
  }
};

void draw() {
  background(248);
  translate(width / 2, height / 2);
  drawShape(radiusArray);
}

void drawShape(float[] radiusArray) {
  int resolution = radiusArray.length;
  beginShape();

  // Make the last three points the same as the first three.
  for (int i = 0; i < resolution + 3; i++) {
    int index = i % resolution;
    float angle = ((float)i / resolution) * TWO_PI;
    
    curveVertex(
      radiusArray[index] * cos(angle),
      radiusArray[index] * sin(angle)
    );
  }
  
  endShape();
}