It's possible to directly connect an iPhone to an iPad via a Lightning cable. To create a dual-sided Lightning cable, just take a regular Lightning cable and connect the USB end to a Lightning to USB Camera adapter. This, in essence, creates a Lightning to Lightning cable that can be used to directly connect an iPhone to an iPad.
This setup is a novelty to do just because you can. In practice, I find that it adds little value in terms of transmission speed. Still, it's cool that it can be done at all, which is why I thought I'd share it with you.