The Forerunners work in mysterious ways, such as granting us beautiful new Halo 4 art via an Xbox Live Marketplace premium theme.

The new art, spotted by The Little English Halo Blog, shows what looks like a UNSC Pelican (could it be the ship Chiefy was napping in at the end of Halo 3?) sailing through the sky past enormous, upside-down structures, as well as some sort of high-tech bridge or ship deck.

Your guess is as good as ours as to what these images could actually represent, but if the final game looks anything like this then color us excited.

Give us your best guesses in the comments or on Twitter.

[via Joystiq]