A method and system for combining paper-driven and software-driven design processes is provided. An example system comprises a request detector, a stroke analyzer, and a UI definition updater. The request detector may be configured to detect a request to process a change to a UI definition. The stroke analyzer may be configured to access a stroke generated by a digital pen and determine, from the stroke, a new element to be appended to a page in the UI definition. The UI definition updater may be configured to update the UI definition, e.g., by including the new element at the target location.