You stand on a craggy mountaintop, alone. The only living thing from horizon to horizon. A few other thin, barren peaks thrust up through the clouds like stone needles stuck into the sky. It’s freezing cold yet the ground remains free of snow. The moon waxes full and strange. You don’t recognize any of the stars. Only one thing is certain. This vista is but a window unto something else. Something bizarre and terrifying. Gaze deep enough, and it will gaze back, from unknowable depths and voids where nothing should exist. Perhaps it will extend an invitation. Enter the world of Euclidean, where inscrutable dangers lurk around every corner and your pleas for mercy will go unheard.