create drupal block

<?php
// $Id:  hello module Exp $
 
// keep the module name consistent throughout
global $moduleName;
$moduleName = "hello";
 
// call menu hook to create an administration menu to create content for your hello module
function hello_menu() {
global $moduleName;
  $items = array();
  $items['admin/settings/'.$moduleName] = array(
    'title' => ucfirst($moduleName),
    'description' => 'Set '.$moduleName.' code',
    'page callback' => 'drupal_get_form',
    'page arguments' => array($moduleName.'_admin'),
    'access arguments' => array('access administration pages'),
    'type' => MENU_NORMAL_ITEM,
   );
  return $items;
}
 
// call admin hook to let you administrate the content of this hello block
function hello_admin() {
global $moduleName;
  $form = array();
    $form[$moduleName.'_show_title'] = array(
    '#type' => 'checkbox',
    '#title' => t('Show title'),
    '#default_value' => variable_get($moduleName.'_show_title', '1'),
    '#required' => TRUE,
  );
  $form[$moduleName.'_number'] = array(
    '#type' => 'textfield',
    '#title' => t('How many blocks'),
    '#default_value' => variable_get($moduleName.'_number', '1'),
    '#maxlength' => 3,
    '#required' => TRUE,
  );
  $n = (int)variable_get($moduleName.'_number',1);
  for( $i=1;$i<$n+1;$i++ ) {
    ($i<2) ? $setreq = TRUE : $setreq = FALSE;
   $form[$moduleName.'_'.$i] = array(
  '#type' => 'textarea',
  '#title' => t(ucfirst($moduleName).' Block '.($i)),
  '#default_value' => variable_get($moduleName.'_'.$i, ''),
  '#maxlength' => 800,
  '#required' => $setreq,
  );
  }
  return system_settings_form($form);
}
 
// call block hook and show in Drupal block the you assign
function hello_block($op = 'list', $delta = 0) {
global $moduleName;
  $block = array();
  if($op == 'list') {
    for($i=1;$i<variable_get($moduleName.'_number', '1')+1;$i++) {
      $block[$i]["info"] = t(ucfirst($moduleName).($i));
    }
  } else if ($op == 'view') {
    if (variable_get($moduleName.'_show_title', '1')==true)
      $block['subject'] = ucfirst($moduleName);
    $block['content'] = variable_get($moduleName.'_'.$delta, '');
  }
return $block;
}