Soundtrack turns your FedEx tracking number into music and an animated depiction of the package’s journey. If you don’t have one, you can generate one; it’s like a synthy toy where the controls are weights, measures and coordinates. The results are kinda MOR—think library music tracks overlaid upon one another rather than the raw beauty of generative melody—but if you told me 61290980541920196578 was the new face of EDM, who am I to disagree?
Chances are you will have a 14-digit tracking number, which it will refuse due to the 12-digit limit. Skip the first two characters.
Also note that the animation of your ghostly package ends close to the address it was delivered to. It would be easy enough to determine the real-world locations, despite the abstract representation. Share your song URLs at your peril.