In current theories of phonetics, the very concept of syllable structure is problematic. More references can be found in this article on ambisyllabicity in the language of the Rigveda (link). More can be found by googling ambisyllabicity. (Some languages even allow words that have a-syllabic words, along the lines of English shh or Mandarin sz 'four'.)

Ceci n'est pas un seing.