Briar, Thorn
If you look at flowers the first thing you notice are the leaves and petals themselves, then the next thing you notice are the briars. You never see thorns first, only after you've looked at the flowers.
Imagine what you see next after looking at the pretty flowers. The briars are what you see next. Spiky and sharp. It would have been nice if you had seen them first.
し, じ
いばら
None
When you see the briars you can't help but yell, Eee! Ba riars! (いばら)! You pause funny because you prick your finger on one while you're yelling. Ouch!
Imagine seeing the briars and yelling out "Ba RI ars!" as you prick your finger on one.