Fold Protractor: Angle Finder

Fold Protractor turns iPhone Duo into a bevel gauge. Open the phone, set it into a corner or against two edges, and read the hinge angle in big numbers. • Inside or outside angle • Hold to freeze the reading • Calibrate at flat (180°) or at 90° • Haptic ticks every 45° • Target: pick an angle. The screen is red until you reach it, then green. On every other iPhone, and on a folded Duo, it works as a level. Stand the phone on an edge to read its rotation, or lay it flat to see the surface tilt with a bubble. Lock sets the current angle as zero, so you can measure from any edge. In level mode, rulers run down both long edges: centimeters on the left, inches on the right. They count from the top of the phone itself, not the screen, and are set for each iPhone model from Apple's published measurements. On iPhone Duo, open the phone and rulers also run along the long edges of the inner…