Color, made up of hue, saturation, and value, dispersed over a surface is the essence of painting, just as pitch and rhythm are the essence of music. Color is highly subjective, but has observable psychological effects, although these can differ from one culture to the next. Black is associated with mourning in the West, but in the East, white is. Some painters, theoreticians, writers and scientists, including Goethe, Kandinsky, and Newton, have written their own color theory.
Painters work both indoors and out. Outside work is done in relatively mild weather. In some jobs, especially maintenance and redecoration of offices and buildings, the painter may be required to work evenings or weekends. Work is seasonal; however, new materials and methods tend to give more steady employment throughout the year. Physical and health hazards include the dangers of poisoning, falling from ladders and scaffolds, breathing paint fumes and dust. The work involves standing, bending, climbing and working with arms over the head much of the time.
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.
In Python 2.4a3 (to be released this Thursday), everything remains as currently in CVS. For 2.4b1, I will consider a change of @ to some other single character, even though I think that @ has the advantage of being the same character used by a similar feature in Java. It's been argued that it's not quite the same, since @ in Java is used for attributes that don't change semantics. But Python's dynamic nature makes that its syntactic elements never mean quite the same thing as similar constructs in other languages, and there is definitely significant overlap. Regarding the impact on 3rd party tools: IPython's author doesn't think there's going to be much impact; Leo's author has said that Leo will survive (although it will cause him and his users some transitional pain). I actually expect that picking a character that's already used elsewhere in Python's syntax might be harder for external tools to adapt to, since parsing will have to be more subtle in that case. But I'm frankly undecided, so there's some wiggle room here. I don't want to consider further syntactic alternatives at this point: the buck has to stop at some point, everyone has had their say, and the show must go on.
In object-oriented programming, the decorator pattern is a design pattern that allows behavior to be added to an individual object, dynamically, without affecting the behavior of other objects from the same class. The decorator pattern is often useful for adhering to the Single Responsibility Principle, as it allows functionality to be divided between classes with unique areas of concern. The decorator pattern is structurally nearly identical to the chain of responsibility pattern, the difference being that in a chain of responsibility, exactly one of the classes handles the request, while for the decorator, all classes handle the request.
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.