I found this idea recently and I think it's so clever. I wanted to share it with you. Naturally, I couldn't follow the tutorial like she had it, because I found ways to improve upon it and I'm a cheapskate. If you like her's better, follow her tutorial.
All you will need is some paper/cardstock (I found it works well with paper on the outside cardstock on the inside, but as long as you're not doing both layers a thin piece of paper, you're alright. I also strongly encourage double-sided paper. At least for the outside. It doesn't have to be the same on both sides, but something you are okay with seeing) and some glue. My daughter picked out the sparkly green and I got pretty excited about these scraps of light green that will work perfectly for this project so I don't have to feel hoarder-ish for not throwing them away.
Cut the inside pieces to be 4"x 1". She scored hers first. If you have that luxury and are not using scraps, you can, too. I'll explain scoring them in the next step. For the outside, you'll need a 1"x 9 1/2" and a 1"x 6" piece (hers were 6 1/4". I thought that was a total waste of paper! I could get twice as many from 6" and that extra 1/4 inches made the second half of the 12" paper totally unacceptable for this project. 6" was doable. It means I have to trim the bottoms of the shamrocks if I want them totally even, but honestly, I found I had to do that anyway)
If you didn't already, score your 1"x 4" papers at 1" intervals, at 1", 2", and 3". I folded mine already to show what they will look like. Then take your 9 1/2" piece of paper and create notches at 1 1/2" and 8" marks (I found it MUCH easier to mark the 1 1/2" and cut them together. It made everything lay smoother and it saved me from cutting and measuring twice unnecessarily. On the other side, at 4 3/4", make a slightly bigger notch. On the 6" strip, mark and snip at 1 3/8". The notches in my picture were cut thicker than I did for the rest so that you could see them. I honestly only cut slits and then put a gap in the center of the long strip. It depends on which way you'd like to be lazy, getting them to fit together easily by cutting a bit deeper of a groove, or spending an extra second or two getting the slits to work together. I chose the latter. Also, slightly curve your cardstock inward before you start working with it so that it doesn't bend and crease in an undesirable place.
Take the long strip and loop both outside grooves into the center groove. Nest them together. Then gently loop the shorter paper and slip it into the center groove of the long strip. You will end up with this shape.
Take the scored strips and fold them at the inch marks. Wedge them into the loops. I found it most helpful to put the center one in first.
When they're all in, the shamrock has a nice shape.
The tutorial says glue the ends together. It doesn't say clip the ends so that they're even, and honestly I like the slightly shorter insides from when I modified the center loop, but you can clip them even if you'd rather. We didn't glue ours together yet. Maybe we will... But the paper that fans a bit looks pretty neat, and ours are going with a goodie bag, so I might just holepunch them and tie them on?
Here's all 17 of our shamrocks! To make 17, it took 2 whole 12x12's and half of another. Part of that was needing more centers, and I'm guessing if I hadn't had the scraps, it would have taken all 3 sheets in their entirety You could calculate it with the math (1 12"x 1" strip for the inside, 1 1/2 12"x 1" strips for the outside, per shamrock) but I don't mind not knowing exactly, so I'm not going to bother...