Syntactic constraints. Python is a syntactically simple language with fairly strong constraints on what can and can't be done without "messing things up" (both visually and with regards to the language parser). There's no obvious way to structure this information so that people new to the concept will think, "Oh yeah, I know what you're doing." The best that seems possible is to keep new users from creating a wildly incorrect mental model of what the syntax means.
The decorator pattern, also known as the wrapper pattern, is when you wrap an object within another object, thus providing a means of enhancing or overriding certain behavior. The wrapper object will delegate any incoming method calls to the original object, unless it defines a new method to enhance or replace the original object’s behavior. By using the decorator pattern, you can dynamically create as many decorated objects as you want, each enhancing the behavior of the original object in a unique way — and all without mutating the original object. In this manner, you can effectively add, remove, or extend behaviors at runtime.
A still life is a work of art depicting mostly inanimate subject matter, typically commonplace objects—which may be either natural (food, flowers, plants, rocks, or shells) or man-made (drinking glasses, books, vases, jewelry, coins, pipes, and so on). With origins in the Middle Ages and Ancient Greek/Roman art, still life paintings give the artist more leeway in the arrangement of design elements within a composition than do paintings of other types of subjects such as landscape or portraiture. Still life paintings, particularly before 1700, often contained religious and allegorical symbolism relating to the objects depicted. Some modern still life breaks the two-dimensional barrier and employs three-dimensional mixed media, and uses found objects, photography, computer graphics, as well as video and sound.
In England, little is known of the trade and its structures before the late 13th century, at which paint guilds began to form, amongst them the Painters Company and the Stainers Company. These two guilds eventually merged with the consent of the Lord Mayor of the City of London in 1502, forming the Worshipful Company of Painter-Stainers. The guild standardised the craft and acted as a protector of the trade secrets. In 1599, the guild asked Parliament for protection, which was eventually granted in a bill of 1606, which granted the trade protection from outside competition such as plasterers.
Portrait paintings are representations of a person, in which the face and its expression is predominant. The intent is to display the likeness, personality, and even the mood of the person. The art of the portrait flourished in Ancient Greek and especially Roman sculpture, where sitters demanded individualized and realistic portraits, even unflattering ones. One of the best-known portraits in the Western world is Leonardo da Vinci's painting titled Mona Lisa, which is thought to be a portrait of Lisa Gherardini, the wife of Francesco del Giocondo.
In 1890, the Parisian painter Maurice Denis famously asserted: "Remember that a painting—before being a warhorse, a naked woman or some story or other—is essentially a flat surface covered with colors assembled in a certain order." Thus, many 20th-century developments in painting, such as Cubism, were reflections on the means of painting rather than on the external world—nature—which had previously been its core subject. Recent contributions to thinking about painting have been offered by the painter and writer Julian Bell. In his book What is Painting?, Bell discusses the development, through history, of the notion that paintings can express feelings and ideas. In Mirror of The World, Bell writes:
Encaustic painting, also known as hot wax painting, involves using heated beeswax to which colored pigments are added. The liquid/paste is then applied to a surface—usually prepared wood, though canvas and other materials are often used. The simplest encaustic mixture can be made from adding pigments to beeswax, but there are several other recipes that can be used—some containing other types of waxes, damar resin, linseed oil, or other ingredients. Pure, powdered pigments can be purchased and used, though some mixtures use oil paints or other forms of pigment. Metal tools and special brushes can be used to shape the paint before it cools, or heated metal tools can be used to manipulate the wax once it has cooled onto the surface. Other materials can be encased or collaged into the surface, or layered, using the encaustic medium to adhere it to the surface.
Water miscible oil paints (also called "water soluble" or "water-mixable") is a modern variety of oil paint engineered to be thinned and cleaned up with water, rather than having to use chemicals such as turpentine. It can be mixed and applied using the same techniques as traditional oil-based paint, but while still wet it can be effectively removed from brushes, palettes, and rags with ordinary soap and water. Its water solubility comes from the use of an oil medium in which one end of the molecule has been altered to bind loosely to water molecules, as in a solution.
Modern artists have extended the practice of painting considerably to include, as one example, collage, which began with Cubism and is not painting in the strict sense. Some modern painters incorporate different materials such as sand, cement, straw or wood for their texture. Examples of this are the works of Jean Dubuffet and Anselm Kiefer. There is a growing community of artists who use computers to "paint" color onto a digital "canvas" using programs such as Adobe Photoshop, Corel Painter, and many others. These images can be printed onto traditional canvas if required.