int xspacing = 10;
int w;
float theta =0.0;
float amplitude = 5.0;
float period = 20.0;
float dx;     
float[] yvalues;     

void setup() {
  size(200,200);
 
  w = width+16;
  dx = (TWO_PI / period) * xspacing;
  yvalues = new float[w/xspacing];
}

void draw() {
  background(255);
  //tree
  fill(12,134,29);
noStroke();
triangle(100,30,60,70,140,70);
triangle(100,20,70,50,130,50);
triangle(100,40,50,90,150,90);
triangle(100,50,40,110,160,110);
triangle(100,60,30,130,170,130);
triangle(100,70,20,150,180,150);


fill(132,92,56);
noStroke();
rect(80,150,40,30);

//light
  calcWave();
  renderWave();

}

void calcWave() {
theta +=0.02;

    float x = theta;
  for (int i = 0; i < yvalues.length; i++) {
    yvalues[i] = sin(x)*amplitude;
    x+=dx;
  }
}

void renderWave() {
    for (int x = 0; x < yvalues.length; x++) {
    noStroke();
    fill(255,248,101);    
    ellipse(x*xspacing,width/2+yvalues[x],10,10);
  }
}