Also good to know these patterns if you're dealing with a lot of legacy code, particularly 199x - 201x code that implemented a lot of these patterns. Some of t

Also good to know these patterns if you're dealing with a lot of legacy code, particularly 199x - 201x code that implemented a lot of these patterns. Some of them are straightforward (factory, adapter). Some of them are almost never used (flyweight). Some are more particular to a programming language; you might see a lot of visitor patterns in C++ code, for instance, but IIRC, that wouldn't come up in Smalltalk because it supported paradigms like double dispatch out of the box.