Processing sample 2

drawRainbow2

final int RED        = 0;
final int ORANGE     = 1;
final int YELLOW     = 2;
final int GREEN      = 3;
final int BLUE       = 4;
final int INDIGOBLUE = 5;
final int PURPLE     = 6;

int COLORMAX = PURPLE;
final int RAINBOWSIZEMAX = 250;
final int RAINBOWWIDH    = 25;

void setup() {
    size(940, 235);
    noStroke();
    background(200,242,255);
}

void draw() {

    float w = random(width);
    float h = random(height-30, height);

    if(frameCount % 2 == 0) {
      filter(BLUR, 4);
    }
    for(int i=RED; i<=COLORMAX; i++) {
        strokeRainbowColor(i);
        strokeWeight((RAINBOWWIDH / 2) + 1);
        fill(0, 0, 0, 0);
        arc(w, height,
          RAINBOWSIZEMAX - (i*RAINBOWWIDH), RAINBOWSIZEMAX- (i*RAINBOWWIDH),
          -PI, 0);
    }
}

void strokeRainbowColor(int count)
{
    int check = count % (COLORMAX+1);
    switch(check) {
      case RED:
        stroke(237, 26, 61);
        break;
      case ORANGE:
        stroke(255, 183, 76);
        break;
      case YELLOW:
        stroke(255, 212, 0);
        break;
      case GREEN:
        stroke(0, 128, 0);
        break;
      case BLUE:
        stroke(0, 103, 191);
        break;
      case INDIGOBLUE:
        stroke(35, 71, 148);
        break;
      case PURPLE:
        stroke(167, 87, 168);
        break;
      default:
        strokeRainbowColor((COLORMAX+1)+check);
        break;
    }
}