Double Boon

Several early Magic sets had multiple alternate art pieces for the same card. One such set was Alliances, in which the card Phyrexian Boon was slated to get two collectible pieces of art.

Mark Tedin elected to illustrate the two Phyrexian Boon pieces as one continuous mural. Check it out:

Art by Mark Tedin

You can see how it was split up on the two cards:

The card Serra's Boon from Planar Chaos, as Matt Cavotta reported earlier, contains a particularly close art homage to the left half of Tedin's Phyrexian Boon art.