ScEngGUI
SceneEngine is designed as a pure c++ library without any user interface elements.
The ScEngGUI is a Graphical User Interface layer between SceneEngine and CrackArt. The ScEngGUI is a set of virtual classes that connect CrackArt to SceneEngine at different levels.
BlockGUI
The BlockGUI is the class that tells CrackArt how a SceneEngine Block works.