Corner Spiral - RGB

A single unbroken line starts in the corner of a 4096×4096 canvas, slides along the top wall, turns down the right wall, along the bottom, up the left, then shrinks inward ring by ring until it reaches the center, one continuous path, 16,777,216 steps long, never crossing itself. Every one of the 16,777,216 possible RGB colors appears exactly once along that path, and they're placed by walking smoothly through the RGB color cube itself, so red, green, and blue all drift together in small steps. The result is a hypnotic set of concentric square rainbow bands, evenly paced, glowing red at the very center and cycling outward through orange, yellow, green, blue, and magenta before fading at the outer wall.