[ Snorting, Merlin let go of the hand finally and leaned back in his seat. ] No, it's not just a picture. It's a communication device. One that can be used from a world to another and furthermore, used for travel.

[ It was a bit more than that but he didn't want to go into the metaphysics of it.

For his purposes it was just a device to make communication easier when not on the same plane of existence, really. Trumps could be used as protection, anchors, spying devices, and more. But Merlin rarely bothered. He had other means for those things, less hazardous means for those exact purposes. ]