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2.3 Conceptual models 53

number of forecasts-greatly extending what they could do before with existing
tools.
Another popular accounting tool intended for the home market, based on a con-
ceptual model of an object, is Quicken. This used paper checks and registers for its
basic structure. Other examples of conceptual models based on objects include most
operating environments (e.g., Windows and the Mac desktop) and web portals. All
provide the user with a familiar frame of reference when starting the application.