Hello, we routed V-shaped grooves in an acrylic panel using a CNC milling machine and placed the panel in front of my window, with no direct light hitting it. The pictures below show two cases, in the top picture, the grooves are facing the window and on the bottom one the grooves are facing us. Note that when the grooves are facing us, the diffused light seems to have been captured. I cannot explain how this is happening but would like to use this technique to harvest light in a building similarly to this old technique called "Prismatic Glass": http://files.umwblogs.org/blogs.dir/7608/files/glass/prismatic.pdf How is the diffused light captured or redirected since it has no clear direction unlike direct light? How can you explain the differences in luminescence in the two picture below under diffused light?