function drawing_canvas() {
  $canvas = array(                                                                                        
    '#type' => 'canvas',
    '#children' => TRUE,
    );  
      
  $canvas['ellipse2'] = array(
    '#type' => 'ellipse',
    '#cx' => '400px',
    '#cy' => '200px',                                                                                     
    '#amaj' => '100px',                                                                                   
    '#amin' => '50px',
  );  
  $canvas['ellipse1'] = array(
    '#type' => 'ellipse',                                                                                 
    '#cx' => '400px',
    '#cy' => '200px',
    '#amaj' => '200px',                                                                                   
    '#amin' => '100px',
  );    
  return $canvas;                                                                                         
}