  We present our game, Cube2Pipes, as an attempt to investigate a unique
gameplay design where we use a tangible 3D spatial puzzle, in the form of a 2X2
Rubik's Cube, as an interface to a tabletop mobile augmented reality (AR) game.
The game interface adapts to user movement and interaction with both virtual
and tangible elements via computer vision based tracking. This game can be seen
as an instance of generic interactive hybrid systems as it involves interaction
with both virtual and real, tangible elements. We present a thorough user
evaluation about various aspects of the gameplay in order to answer the
question as to whether hybrid gameplay involving both real and virtual
interfaces and elements is more captivating and preferred by users, than
standard (baseline) gameplay with only virtual elements. We use multiple
industry standard user study questionnaires to try and answer this question. We
also try to determine whether the game facilitates understanding of the spatial
moves required to solve a Rubik's Cube, and the efficacy of a tangible puzzle
interface to a tabletop AR game.
