(Tanka is the historical antecedent that evolved into renga. Renga is a chain of related verses in the format 17-14-17-14-17-14 etc. Haiku was originally one verse extracted from the chain that would stand on its own. It has become more common than renga. In renga, one writer would do one verse, then the next would write a connected verse with a slight difference, but using the alternative syllable count. If the previous one was 14, then the next would be 17. Like the picture association game except using text verses instead, but with a very structured form.
If you read the biographies of some of the well known haiku writers, they sound very Aspie. Renga, IMHO, sounds like a bunch of Aspies communicating.)
tanga is ancient
renga is a chain in verse
haiku stands alone
_________________
"The voyage of discovery lies not in finding new landscapes but in having new eyes." - Marcel Proust