iHandy Carpenter - An handy carpenter tool kit right on your device! There are 5 tools in this Carpenter tool kit:
Notation Pad - Notation Pad is the Easiest way to write sheet music with notations on iOS/Android.
Angle Finder™ - Angle Finder™, now rebranded to Protractor+, is an app that offers a handy protractor tool on your phone.
Orpheus App - Sheet Music Reader for Android
Pocket Ruler AR - Pocket Ruler AR is a pocket ruler app that lets you measure objects and distances with your phone.
Symphony Pro - Complete music notation and composition app for iPad.