When code is executed as PaperScript, the script's scope is populated with
all fields of the currently active PaperScope object, which within
the script appear to be global.
global scope, referencing the currently active PaperScope object,
through which all properties and Paper.js classes can be accessed.
Global PaperScript Properties
PaperScript View Event Handlers
PaperScript Tool Event Handlers
Keyboard Event Handlers (for PaperScript)