This is rule three from Donald Hoffman's book Visual Intelligence (see Raphael link #2 and #3). When we see two lines like this our brains read them as if they were parts of the same line in 2D and in 3D. The next illustration fills it in. (-> # 12)
This is rule three from Donald Hoffman's book Visual Intelligence (see Raphael link #2 and #3). When we see two lines like this our brains read them as if they were parts of the same line in 2D and in 3D. The next illustration fills it in. (-> # 12)