polytropos' photos with the keyword: optical illusion

Macro Mondays – Mo. 04.05.2020: Diagonale Linien Do you can see the optical illusion? In the main picture it looks as the tiles are swales (concave). In the thumbnail (PiP 1) which is the same picture, you can see that is not! The tiles are elevated (convex), as it should be. It's the same effect as ► HERE (in PiP 4). This effect is called ► The Hollow-Face Illusion. Why this effect appears here (at same picture with different size) I can not answer. :-) ► PiP 1: thumbnail 100x100 of the main pic. ► PiP 2: version 240x240 of the main pic. ► PiP 3: version 500x500 of the main pic. ► PiP 4: the tiles.

... in fact "Cubus-X" is a chain made from several triangular pyramids or irregular tetrahedrons (see PIP 1) that can be transformed in a lot of other shapes as shown in the other PIPs. => Cubus-X ➽ PIP 1: a chain (or star) ➽ PIP 2: an UFO ➽ PIP 3: an Icosahedron ➽ PIP 4: a Tetrahedron (triangular pyramid) ➽ PIP 5: a "couch" ➽ PIP 6: an optical illusion (cube in a triangle) ➽ Saturday Self-Challenge – Sa. 07.09.2019 , topic: "Cube" The cube is one of the five platonic bodies (tetrahedron, hexahedron, octahedron, dodecahedron, icosahedron), more precisely a polyhedron with six squares as boundary surfaces, twelve edges and eight corners, in each of which three boundary surfaces meet. The cube is a special parallelepiped, a special cuboid and a special straight square prism. And => HERE is an online dice simulator. It is intended for cases where dice need to be thrown but no real dice are available. Click on "Würfeln". ;-)

Saturday Self-Challenge – "Schatten" Steht der Schatten vor oder zurück? :-) Tiefenumkehr ("hollow-face-illusion") ➽ PIP 1: "Rollenverteilung" (unten, Mitte links, sieht man obigen Ausschnitt) ➽ PIP 2: Smile. ➽ PIP 3: Wo gewindet wird, da fallen Splitter. (altes Sprichwort) ;-) ➽ PIP 4: Upside down Version (180° gedreht) (47.04203, 07.66727) ; [10°]