Apps.  are great, but who has time to search for them? Here is my favorite handy design app.: iHandy Carpenter, a handy tool app for  your smart phone has five different tools.  My favorite is the bubble level, great for hanging small pictures in a pinch.  You can also just get the level app. which is a free download. Other tools include a plumb, protractor, ruler, and a surface level (you know for checking up on the tile guy).  What is your favorite phone app.?