For the tracking of the physical input devices we used optical black and white markers, called fiducials. We used the set of fiducials from the reactable project and you can download the markers as a PDF.
Aside from the set of fiducials you need a software to run on your computer. There are lots of possible programmes which can handle the fiducial tracking. You can download the software and get an overview of what is possible on the pages of the reactable software.
TangibleTable was realized in VVVV, which is a very powerful tool for developing realtime-based multimedia applications such as motion-graphics, sound and video or multiuser environments.
To get more information about the programming in VVVV, check the Programming section.