Followup (3/23/13): I like to imagine I influenced this design with this instructable. (Though I'm probably just tuned into some trend somehow)
Step 2: Cut twice
cut it once through the top layer from the middle of the neckline down to the bottom
Step 3: Pin together
Step 4: Finis
Okay, this is not a serious garment, but if you were to wear it for realz, you might want to do something like super glue the safety pins shut so they don't come undone and stab you one random day...