“…Some drawbacks are identified by their respective authors, such as that the users are tied to a fixed location (Dietz & Leigh, 2001) (Dohse, Dohse, Still, & Parkhurst, 2008), the recognition is not very accurate when several users are working on the same side of the table (Dohse, Dohse, Still, & Parkhurst, 2008), and the number of users is limited (Dietz & Leigh, 2001) (Harrison, Sato, & Poupyrev, 2012) (Marquardt, Kiemer, Ledo, Boring, & Greenberg, 2011) (Meyer & Schmidt, 2010) (Roth, Schmidt, & Güldenring, 2010). Also, the use of wearable hardware (Marquardt, Kiemer, Ledo, Boring, & Greenberg, 2011) (Meyer & Schmidt, 2010) (Roth, Schmidt, & Güldenring, 2010) may result uncomfortable for some people, and it usually requires a previous registration from the users (also observed in (Schmidt, Chong, & Gellersen, 2010)), which is not a very natural way of starting the interactions.…”