Tartan is a pattern consisting of criss-crossed horizontal and vertical bands in multiple colours. Tartans originated in woven wool, but now they are made in many other materials.
Wallpaper designs in graphic backgrounds convey "home". They can be used to create an appearance of a room in backgrounds for games and apps. These two different classical wallpaper styles are superimposed to create an interesting visual effect, as the scale of the top transparent image changes on scrolling or window resize.
Op art works are abstract. When the viewer looks at them, the impression is given of movement, hidden images, flashing and vibration, patterns, or alternatively, of swelling or warping.
A moiré is created when two grids are overlaid at an angle, or when they have slightly different mesh sizes.
The exact origin of the lemon has remained a mystery, though it is widely presumed that lemons first grew in Southern India, northern Burma, and China. In South and South East Asia, it was known for its antiseptic properties and it was used as an antidote for various poisons.
Symmetric patterns occur in nature and were artistically rendered in a multitude of forms, including the bewildering graphics of M. C. Escher. Nonetheless, it was not until the second half of 19th century that the unifying role of symmetry in foundations of geometry had been recognized.