Did a much-needed solo retreat from Feb 1-17th at Grayton Beach, Florida, on the Gulf Coast, in a nice little cabin in that sleepy little beach town. I mostly focused on the Fire Kasina (candle flame) with some counterbalancing doses of Water Kasina (ocean), Air Kasina (sky), and Earth Kasina (beach sand). I did other practices, loving-kindness, equanimity, multiple magickal practices, other jhanic practices, but mostly it was straight-up kasinas.
I also spent a reasonable amount of time using one of the round inset ceiling lights over the couch as a Light Kasina, staring at it, closing my eyes, dropping a hood over my face, and focusing on the resultant show, which produced a larger nimitta than the candle, obviously, as the light was about 10cm (4 inches) wide. The middle of the nimitta had a lot more room to get very interesting, morph into cartoon images, and glow as a bright white light with internal ripples and shimmers, finally progressing through various odd changes, including spinning splines of green and pink over a black background, to become the White and Gold, and finally the Molten White Gold that moved extremely fast with incredible intricacy in large swaths towards the top of the visual field.
After about a week of kasina practice, typically doing about 10-14 hours per day of meditation of various kinds, I was walking on the beach at night on a somewhat cloudy night and suddenly noticed yellow light dancing across the ridges of sand on the beach, like someone was raking it with a flashlight held low to the ground. I looked around: nobody there, no lights on, nothing but a bit of silver moonlight through the clouds, nothing that would produce yellow flickering light to illuminate the beach. The light would come and go, wax and wane, shimmer, flicker, dance, and finally became a moderately bright steady glow that momentarily convinced me there must be a vehicle pulling up behind me on the beach and this must be its headlights, so I looked around, but nothing was there but the light without a source.
This happened numerous times during three different nighttime walks on the beach, at time being so strong it appeared as if numerous cars had bright headlights pointed on the beach, but no cars were there, no lights came from the houses far away down the beach, nothing like that came from the moon or stars, no helicopters flew overhead at that time (though they routinely did patrol the beach, presumably part of the Coast Guard). When the light would get really bright, it seemed that I could literally see the sand as one would see it in early morning or in the evening before dusk, with remarkably enhanced detail of the features of the beach.
I finally got used to the phenomenon and stopped looking for the source, which appeared to be a side-effect of the Light Kasina, for, as the ancient texts, such as the Visuddhimagga and Vimuttimagga say, “One who practices the Light Kasina sees light everywhere.”