Learning a new software application can be a challenge, requiring the user to enter a new environment where their existing knowledge and skills do not apply, or worse, work against them. To ease this transition, we propose the idea of cross-application bridges that start with the interface of a familiar application, and gradually change their interaction model, tools, conventions, and appearance to resemble that of an application to be learned. To investigate this idea, we developed Blocks-to-CAD, a cross-application bridge from Minecraft-style games to 3D solid modeling. A user study of our system demonstrated that our modifications to the game did not hurt enjoyment or increase cognitive load, and that players could successfully apply knowledge and skills learned in the game to tasks in a popular 3D solid modeling application. The process of developing Blocks-to-CAD also revealed eight design strategies that can be applied to design cross-application bridges for other applications and domains.