Bar graphs

int howMany = 15;
float step, edge;
ExLine [] Elem = new ExLine[howMany];

void setup() {
  size(500, 400);
  background(#2C3E50);
  noStroke();
  float x = 0;
  float theta = 0;
  edge = width/10;
  step = (width-2*edge)/howMany;
  for (int i = 0; i < Elem.length; i++) {
    x = i*step;
    Elem[i]= new ExLine(x, theta);
    theta += PI/howMany;
  }
}

void draw() {
  background(#2C3E50);
  for (int i = 0; i < Elem.length; i++) {
    Elem[i].display();
  }
}
class ExLine {
  float x, x2, y, y2;
  float rad, theta;

  ExLine(float _x, float _theta) {
    x = _x;
    y = height*.6;
    rad = 70;
    theta = _theta;
  }

  void display() {
    y2= map(sin(theta), -1, 1, -30, -120);
    x2 = map(sin(theta), -1, 1, step*.4, step*.9);
    rect(x+edge, y, x2, y2);
    theta += .0523;
  }
}