This is a photo from our little walk on Christmas Day (short because of the cold). It’s the water of a little stream just before is runs down a mini-barrage. Before the stream opens to a small pond with almost no movement, that’s why it is frozen. When reaching the barrage it is running faster again and the ice didn’t have a chance yet.
Here is how the small barrage looked like, the ice slowly growing in from the sides.
Photo data: Pentax K20D, 50-200 mm lens at 200 mm, f5.6, 1/125 second and ISO 200