I am a factotum class. My instances represent Smalltalk blocks, portions
of executeable code that have access to the environment that they were
declared in, take parameters, and can be passed around as objects to be
executed by methods outside the current class.
Block closures are sent a message to compute their value and create a new
execution context; this property can be used in the construction of
control flow methods. They also provide some methods that are used in the
creation of Processes from blocks.