As you can see, I am not the most creative person in the world.
I used a disposable pastry bag and the smallest round-hole tip. Oh, yes, I learned recently that they're number-coded: It was a #2. I had some trouble keeping the pressure steady, which is why some of the shapes are raggedy. The music note, G-clef, heart and squiggles look good to me.
For those who haven't done this: You pipe the chocolate in a thin stream onto parchment paper. It hardens and sets, and then you can lift the whole thing off - carefully - and place it on top of a cake or cupcake. I didn't have any iced cupcakes handy, but I imagine if you put the chocolate decoration on top of frosting, it will more or less stick there.
The background of the photo above looks a little funky and dirty because I had the chocolate on top of a white plastic cutting board that's seen a bit of action.
So here's a question: Can you get the same effect using a zip-top bag with the corner snipped off? Because, if so, that is absolutely what I'm doing next time. Cleaning the melted chocolate off the coupler and out of the decorating tips was a pain in the ^$$. Thank you, kindest husband, for going at them with an old toothbrush.