This is the cover art as it is originally drawn. It was beautifully made by Tord K. Øverland, based on a concept by Torbjørn Øverland Amundsen. If you haven’t already noticed, the picture is a so-called revolving picture, meaning that the left side is perfectly aligned with the right side. The concept is based on a Möbius strip.
You can click on the picture to see an even bigger version.