I am playing with a small personal fan and I noticed that when the blades are moving at some frequency that "lines up" with my monitor refresh rate frequency, they appear blurry and stationary, but with altered shapes. Not only that, but certain edges of the blades are colored blue, while the other blades appear red. I attached a rough drawing of the phenomena. I know this picture is hard to make sense of, but when this little fan is rotating, it seems to make weird clumps of black that are always bounded by the circle of the blades, but are not necisarrily the same shape as the blades. Also this picture is made as if you were me looking at the phenomena as I started writing this post. I have been searching the internet for this effect since this weekend. No one knows about this, and I am really curious how this works.