Despite the widespread usage of mobile devices there is a lack of environments able to allow end users to create applications directly in such devices. In this paper, we present the Puzzle framework, which supports a visual environment for opportunistically creating mobile applications in touch-based mobile phones. The user interface is designed to be usable for mobile users that do not use programming languages in their daily work as well as to motivate end users to playfully experiment and create applications. In particular, we report on its user interface, framework and evaluation.