The way I made these little circle motifs was just to find some cool dinosaur clip art and put it into PowerPoint. Then I made a little light gray circle to go around each dinosaur so when I printed them I'd know where to cut. Finally, I added "Happy Birthday" so it fit inside my circles. I think they measured about two inches or so, but it doesn't have to be precise. Here are the rest of the instructions:
Step 1: Bake some cupcakes and frost them
Step 2: Crush some Oreos
Step 3: Smush the Oreos on top of the cupcakes
Step 4: Cut out your circle motifs
Step 5: Cut a bunch of straws into three equal parts; cut a slit into the end of each segment
Step 6: Slide the circles into the split straws and stick them into the cupcakes
When people ask my kiddo about his birthday party, the dinosaur cupcakes are the first thing mentioned, so I know they were a hit with him.