The Squeak programming language is a dialect of Smalltalk. Reflection is a feature of dynamic, interactive languages such as Smalltalk and Lisp. Pharo relies on a virtual machine that is written almost entirely in Smalltalk itself. Object-oriented features were taken from C++ and Smalltalk. The book includes examples in C++ and Smalltalk. Object-oriented languages like Smalltalk and Ruby have code blocks, whereas Eiffel has agents. Object-oriented programming languages such as Smalltalk and Java usually provide integrated garbage collection. It is used by object-oriented programming languages such as Java and Smalltalk. The design of distributed Smalltalk influenced such systems as CORBA. Smalltalk (c. 1983) pioneered new aspects of JIT compilations. Simula was influential in the development of Smalltalk and later object-oriented programming languages. Objective-C derives its object syntax from Smalltalk. Early examples include Simula, Smalltalk, and Modula-2. GemStone builds on the programming language Smalltalk. Its syntax and execution model were very different from modern Smalltalk variants.