at first this seems contrary to the customs of oo programmingbut you will see any number of cases among the design patterns where we find that inclusion of one or more objects inside another is the preferred method python design patterns the following discuss each of the design patterns featured in the design patterns bookalong with at least one working program example for that pattern the programs have some sort of visual interface as well to make them more immediate to you which design patterns are most usefulthis depends on the individual programmer the ones we use the most are commandfactorydecoratorfacadeand mediatorbut we have used nearly every one at some point references erich gammaobject-oriented software development based on et++(in german(springerverlagberlin erich gammarichard helmralph johnsonand john vlissidesdesign patternselements of reusable object-oriented software (readingmaaddison-wesley james cooperjava design patternsa tutorial (bostonaddison-wesley james coopercdesign patternsa tutorial (bostonaddison-wesley brandon rhodes"python design patterns,