Movable Rainbow Circle

gistfile1.txt

int z = 300;
boolean a = false;
int x = 300;
int y = 300;
int c = 0;
void setup()
{
  size(600, 600);
  frameRate(60);
    colorMode(HSB, 100);

}

void draw()
{
 background(100);
 strokeWeight(20);
 stroke(c, 100, 100);
  circle(x, y, z);
  if ( z <= 300 && z >= 100 && a == false)
  {
    z--;
    z--;
    c++;
    if (z == 100)
    {
      a = true;
    }
  }

  if (z >= 100 && z <= 300 && a == true)
  {
    z++;
    z++;
    c--;
    if (z == 300)
    {
      a = false;
    }
  }
  
  if(key == CODED && keyPressed == true)
  {
    if(keyCode == RIGHT)
    {
      x+=3;
    }
    else if(keyCode == LEFT)
    {
      x-=3;
    }
    else if(keyCode == UP)
    {
      y-=3;
    }
    else if(keyCode == DOWN)
    {
      y+=3;
    }
  }

}