As with all Android projects, the AndroidManifest.xml file under app/src/main/ describes the main components of the application (its activities). Some of the specifics such as the version number and supported SDK range are contained in app/build.gradle instead of the manifest.
All code is under the top-level package
com.xmission.trevin.android.tangram. The sub-packages
are:
.dataJava objects that have little or no dependencies on Android
.exceptionCustom exceptions used for reporting invalid puzzle definitions
.uiClasses that implement the user interface of the application
.utilUtility classes; helper functions
The puzzles that are bundled with the application are located in app/src/main/assets/. All other resources used by the application (UI layout, language-dependent strings, icons, etc.) are under app/src/main/res/.