calcpx is a "pocket" calculator built and engineered from absolute scratch. It is designed with sharp vertical rhythm and a beautiful interface that resembles an object you'd want to hold in your hand. The project was produced through an interview process, and I'm particularly proud of it because of its finished look and feel. The arithmetic AST parser and evaluation are custom on top of a simple view-model layer in ember.js. I provide unit and integration tests of its operator stack and evaluation accuracy.