void draw() {
  // Next frame: displays areas of various figs.
  float h;
  float area; 
  h=80;
  // Small rect.
  area= rArea( h,h+20 );
  text("Areal is" +area,10,10);
  // Big rect.
  h=99;
  area= rArea( h,h+20 );
  text( area, 10, 20 );
  // Circle
  area= cArea( 2*h );
  text( area,10,30 );
  area=cArea( rArea(10,15) );
}

  float rArea( float a, float b ){
    // Calc. area of rect a*b
    float result;
    result= a*b;
    return result/8000;
  }
  
  float cArea( float r ){
    // Return area of circle with radius r.
    float result;
    double pi= 3.14159265;
    area=( pi*r*r );
    return result;
  }