This code does the following:

1) A new global dictionary is created.

2) One by one, the implementing Pico's (i.e. 'real' Pico) functions are added to this environment. This way, they become accessible in the implemented (i.e. the metacircular Pico) Pico.

3) The dictionaries are installed such that the implemented Pico's true, false, eoln and void refer to the corresponding global system variables True, False, Eoln and Void. For True and False this is not possible yet as they are implemented in Pico themselves. See 4) and 5). Therefore, they are temporarily taken to be Void and Void. 3) The primitives implemented im Pico are installed by parsing and evaluating their code. This will also overwrite true and false in the global dictionary, and will thus replace the corresponding Void value.

4) The global system variables True and False can now be looked up in the global dictionary. Notice that this is somehow mind-boggling: the system variables True and False used heavily by the evaluator where implemented in the language by that evaluator itself.