Shiny shells,
A gift from the salty seas,
Of wild waves and surging swells.

Gold and white,
Swaying in the balmy breeze,
Dazzling daisies, a delight.

Together,
Single shell, dozen daisies,
Makes pretty posy for her.

Late on account of a debilitating migraine. But I had fun with this one.

The poetic form is a Treochair - 

"The treochair is an Irish form. While there are quite a few mentions online, the only book that appears to mention it is Robin Skelton's The Shapes of Singing. Here are the basic rules:

Variable number of tercets (or three-line stanzas)Three syllables in the first line, seven in the second, and seven in the thirdThe first line rhymes with the thirdTreochairs employ a lot of alliteration"

~Robert Lee Brewer~