During our trip to Ise (pictures here, here, and here) a few months ago, we found ourselves at a beach around sunset. There was a little trickle of a stream running off from the mountains, down onto the beach.

Nikon D200 + Nikkor 17-55 f/2.8 @ 26mm — ¹/80 sec, f/4.5, ISO 640 — full exif & map — nearby photos

There wasn't much water at the time, but where the flow finally decided to dive into the sand, it left behind a deposit of the sand it was carrying. Over the course of a second or two, this sand would build up enough that it would become a little wall, diverting the water to one side or another. The result was a mesmerizing, constantly updated pattern in the sand.

Nikon D200 + Nikkor 17-55 f/2.8 @ 17mm — ¹/60 sec, f/4, ISO 400, P.P. boost: +1.35EV — full exif & map — nearby photos
Patterns In the Sand

Sometimes it moved laterally quite quickly (inches per second), and sometimes it marched outwards. It was always changing.

Nikon D200 + Nikkor 17-55 f/2.8 @ 48mm — ¹/60 sec, f/4, ISO 400 — full exif & map — nearby photos

Being sunset with clouds on the horizon, it was getting quite dark (and I was still learning to use my new lens), so the picture quality isn't great. The pictures below are after sunset, and through the magic of high ISO, wide aperture, and short exposure, look much brighter than it actually seemed.

Nikon D200 + Nikkor 17-55 f/2.8 @ 34mm — ¹/30 sec, f/2.8, ISO 1250 — full exif & map — nearby photos
Mommy and Child

Nikon D200 + Nikkor 17-55 f/2.8 @ 55mm — ¹/60 sec, f/4, ISO 1250 — full exif & map — nearby photos
25 Minutes After Sunset

For completeness, here's the view 37 minutes prior, before the sun dipped behind the clouds....

Nikon D200 + Nikkor 17-55 f/2.8 @ 55mm — ¹/750 sec, f/14, ISO 400 — full exif & map — nearby photos
12 Minutes Before Sunset