Calcoo is a scientific calculator designed to provide maximum usability. The features that make Calcoo better than (at least some) other calculator programs are: * Bitmapped button labels and display digits to improve readability. * No double-function buttons. * Undo/redo buttons. * Copy/paste interaction with X clipboard. * Both RPN (reverse Polish notation) and algebraic modes are available. * Tick marks to separate thousands. * Two memory registers with displays. * Displays for Y, Z, and T registers. * It is a purely scientific calculator. Features that Calcoo lacks: * Statistical mode. * HEX mode.