// the frequencies as collected during the in class survey
int[] numBirthdays = {1, 1, 1, 2, 4, 5, 4, 1, 4, 2, 1, 6};
int N;
float cx, cy, sz;

void setup() {

  // Compute the total size of population, N
  N = 0;
  for (int n : numBirthdays) {
    N += n;
  }
  
  // Sketch set up...
  size(500, 500);
  smooth();
  background(#D8D4D4);
  noLoop();

  cx = width/2;
  cy = height/2;
  sz = width*0.75;
} // setup()

void draw() {
  color[] colors = {
    color(#D6CDCD), color(#D30404), color(#D1A6A6), color(#D12828), 
    color(#CE7070), color(#CE4D4D), color(#B9DCFF), color(#023467), 
    color(#6395C9), color(#C9A663), color(#FFA703), color(#5F3F03)
  };
  
  // Draw Pie Chart...
  float startAngle = 0;
  float stopAngle = 0;
  
  for (int i = 0; i < numBirthdays.length; i++) {
    float perc = float(numBirthdays[i])/N;
    startAngle = stopAngle;
    stopAngle = startAngle + perc * TWO_PI;
    
    fill(colors[i]);
    arc(cx, cy, sz, sz, startAngle, stopAngle);
  }
} // draw()