Not a lot have been written in the English language, but you'll find a few via:

http://www.google.com/search?q=english+englyn

Thanks for the comments too. There is a problem with the last line, but I'm not too sure how to change it.

Pappa

It's complicated, but imagine a haiku with the additional constraints of rhyme (7th, 8th or 9th syllable of the 1st line rhyming with the last syllables of the 2nd and 3rd lines). Plus various types of consonant or vowel harmonies (repeating patterns of consonants, vowels and rhymes) within each line. This second aspect is called cynghanedd, and the poem contains three forms of cynghanedd; cynghanedd sain on line 1, cynghanedd lusg on line 2 and cynghanedd draws on line 3.

Aside from the strict technical aspects, the poem is meant as a direct appreciation of nature, intentionally using an unusual subject (dung beetles) which are not normally seen as things of beauty or wonder.

Pappa

ps. Thanks for the welcome.