Comparing Crowns of Thorns

On Sunday, Kylee (who blogs at Our Little Acre) posted pictures of her Crown of Thorns plant, euphorbia milii. Kylee was talking about the Crown of Thorns in light of Easter weekend, and she shared some info about its culture as a houseplant as well. Hers blooms a lovely pink-red, but that wasn't what caught my eye.

Scroll down to the second picture on her Green Thumb Sunday post and check out the thorn pattern on Kylee's Crown of Thorns! The thorns on hers are staggered in little groupings. They almost look like tufts of thorns. Now look at mine, in this picture. The thorns on mine are much more random, and seem not to be cozying up to their neighbors at all.

Anyone know why this might be?

Is it a difference between cultivars, or is it just a simple matter of genetic playfulness... like how my college roommate went white/gray at the age of 26, or how a little boy I used to babysit had one blue eye and the other hazel?

I know I sound like a toddler sometimes, with my constant chorus of "Why? Why? Why?" but these things really do make me curious. So any and all theories are welcome!

Oh, and while you experts are checking out my newly rehabbed Crown of Thorns, how about weighing in on these little red buds at the top. More leaves, or maybe... just maybe... the first flowers?

(I hope!)