You know, there are whole workbooks you can buy these days on developing "scissor skills" for your preschooler to be sure their snipping will be up to social standards. I think we have this particular skill covered in our preschool here at Chez Armstrong as Nib so easily demonstrated here.
Curved lines? No problem. He's got it down. Two years old and he's a crack shot with a pair of snips and Mommy has less laundry too! Forget those chi-chi workbooks. Who needs 'em?