Your typical chunk of glacier, after soaking in water for a week or two. The ice is initially very sharp and angular, but over time the surface unfreezes and freezes again, causing the features to ooze together. Any ridges or valleys become smooth at the bottom, like bowls, while the protruding edges remain sharp. The longer the ice is submerged, the more pronounced this effect becomes. Since floating ice tends to keep one section consistently above the water, that section cracks and turns white, while all the rest distorts into the glassy contours you see here.