Tangible User Interfaces (TUIs) are bridges between the digital and physical worlds that we inhabit, making the former accessible and manipulable, by using the real world as a display and as medium for manipulation.

One such instance is the Tabletop tangible interface, or Interactive surface, so called because a horizontal surface is used by one or more people to interact with a digital model.

This is an exploration of possible design solutions for a low-cost and portable Tabletop tangible interface.

Constraint		Strategy 1		Strategy 2
low-cost		already-owned / assumed ownership: smartphone, tablet computer		affordable to own: e.g. rasperry pi
portable		already-carried / assumed on person: smartphone		easy to carry: tablet computer, rasperry pi
tangible		ordinary objects, or possibly some limited set / tokens		"smart" objects: fiducial markers for CV; tokens for capacitive screens; sensor pucks