How to set more childs with own templates to a layout?

Question

I have to create a template programmatically.
And so I need a master template with one child template. That child template again has two child templates.

Now I don't use a layout.xml file I need to call "setTemplate".
But how can I use "setTemplate" for the childs? MAgento can't find these child template because there is no reference to them.

I tried so far:

$layout = Mage::app()->getLayout();
$block = $layout->createBlock('core/template', 'master')
    ->setTemplate('default/html/master.phtml');
$blockChild1 = $layout->createBlock('core/template', 'master.child1')
    ->setTemplate('default/html/child1.phtml');
$blockChild1Child1 = $layout->createBlock('core/template', 'master.child1.child1')
    ->setTemplate('default/html/child1/child1.phtml');
$blockChild1Child2 = $layout->createBlock('core/template', 'master.child1.child2')
    ->setTemplate('default/html/child1/child2.phtml');


$blockChild1->setChild('master.child1', $blockItem);
$blockChild1->setChild('master.child1', $blockTotal);
$block->setChild('master', $blockInvoice);
$html = $block->toHtml();

Answer 1

This is a bit tricky, but here is a working version:

// Get layout
$layout = Mage::app()->getLayout();

// Master block
$master = $layout->createBlock('core/template', 'master')
    ->setTemplate('default/html/master.phtml');

// Child block
$child = $layout->createBlock('core/template', 'master.child1')
    ->setTemplate('default/html/child1.phtml');

// Children 1 block
$children1 = $layout->createBlock('core/template', 'master.child1.child1')
    ->setTemplate('default/html/child1/child1.phtml');

// Children 2 block
$children2 = $layout->createBlock('core/template', 'master.child1.child2')
    ->setTemplate('default/html/child1/child2.phtml');

// Set children 1 to child
$child->setChild('master.child1.child1', $children1);
// Set children 2 to child
$child->setChild('master.child1.child2', $children2);
// Set child to master
$master->setChild('master.child1',$child);

// Master to HTML
$html = $master->toHtml();

The template default/html/master.phtml will contain the following:

echo $this->getChildHtml('master.child1');

The template default/html/child1.phtml will contain the following:

echo $this->getChildHtml('master.child1.child1');
echo $this->getChildHtml('master.child1.child2');

And the templates default/html/child1/child1.phtml and default/html/child1/child2.phtml will contain the HTML or data. Unless you go a level deeper and call 3rd level child.