The ocean horizon on a clear day - my attention directed towards this multiform curtain. Beyond the sea was the unseen future, an alternative to the present. The sky was the boundary to the infinite - shielding us from it. Having stared at the horizon for several minutes, I closed my eyes and released the horizon from this dedicated, determined gaze, as an astronomer releases the cosmos from their grip at the end of the night. I then experienced a slow transition of colors: dark blue / orange, dark orange / light blue-green, and then dark blue / smoky green when I squeezed my eyelids tightly closed. This sequence was a result of retinal adaptation to gazing steadily at the oceanic horizon under these conditions - a biological recording.