This shadowlet appeared on my working counter in the late afternoon one day. The patch of sun was quite small, just big enough to show through the stencils I was using at the time. I got probably half a dozen shots of different images as the sun moved before the opportunity was gone, likely no longer than 15 minutes or so.
There are times in my home during different seasons that shadows appear from the windows onto far walls. Sometimes the shadows are too faint to be picked up well in the photo. You need a pretty strong light source and the other problem capturing these images, as I said before regarding the found birdy, is that the sun moves so quickly that the prime image lasts only a little minute in some cases. Keep your camera handy and watch the walls for interesting shadows, act quickly and you can capture these illusive, fun shadowlets.