The Sense of Order A Book by E. H. Gombrich The Tiling Patterns of Sebastien Truchet and the Topology of Structural Hierarchy perceptionartorder
It doesn't look like anything to me It is related that the bodhisattva Manjusri was once standing at the gate, and seeing him, Shakyamuni Buddha called to him, "Manju, Manju, why don't you come inside the gate?" Manjusri replied, "I don't see anything outside the gate." Kōun Yamada, The Gateless Gate I don't see a wall zen