説明
マザーグースの童謡「This is the House that Jack Built」を暗唱してください。
句や節を別の句や節の中に置く、その過程を埋め込みと呼びます。
再帰と埋め込みという働きがあるからこそ、有限個の形式（語や句）から無限通りの表現を組み立てることができるのです。
さらに、埋め込みを使えば、理論上は無限に長い構造を作ることもできます。
童謡は次のとおりです。
This is the house that Jack built.
This is the malt
that lay in the house that Jack built.
This is the rat
that ate the malt
that lay in the house that Jack built.
This is the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
This is the dog
that worried the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
This is the cow with the crumpled horn
that tossed the dog
that worried the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
This is the maiden all forlorn
that milked the cow with the crumpled horn
that tossed the dog
that worried the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
This is the man all tattered and torn
that kissed the maiden all forlorn
that milked the cow with the crumpled horn
that tossed the dog
that worried the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
This is the priest all shaven and shorn
that married the man all tattered and torn
that kissed the maiden all forlorn
that milked the cow with the crumpled horn
that tossed the dog
that worried the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
This is the rooster that crowed in the morn
that woke the priest all shaven and shorn
that married the man all tattered and torn
that kissed the maiden all forlorn
that milked the cow with the crumpled horn
that tossed the dog
that worried the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
This is the farmer sowing his corn
that kept the rooster that crowed in the morn
that woke the priest all shaven and shorn
that married the man all tattered and torn
that kissed the maiden all forlorn
that milked the cow with the crumpled horn
that tossed the dog
that worried the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
This is the horse and the hound and the horn
that belonged to the farmer sowing his corn
that kept the rooster that crowed in the morn
that woke the priest all shaven and shorn
that married the man all tattered and torn
that kissed the maiden all forlorn
that milked the cow with the crumpled horn
that tossed the dog
that worried the cat
that killed the rat
that ate the malt
that lay in the house that Jack built.
