A Reality-Based Interaction Analysis of Tern


The RBI framework takes into account designer’s consideration for interaction techniques. The idea is that there are reality-based concepts that can facilitate interaction with a system as presented in the publication: “Reality-Based Interaction:A Framework for Post-WIMP Interfaces” by Jacob, et. al..

This framework can be applied to a variety of interfaces to consider the benefits and sacrifices in the design implementation. One such system is Tern, a tangible programming system. Tern consists of physical blocks, tags, a camera, and a computer to create, compile, and run computer programs.

Tern takes advantage of all the RBI themes present: naive physics; body awareness and skills; environment awareness and skills; social awareness and skills. The blocks afford programming syntax by physical constraints (NP). Each block is a command and affords something to follow it or not accordingly; such as a “start” command which is flat on one side and has a peg on the other, allowing for something to follow it but not precede it. Because of the tangible nature of the system, the user is aware of their limbs and their surroundings (BAS and EAS). In addition to supporting environmental and bodily awareness, the physical blocks support a more collaborative interaction as these blocks can be shared and manipulated by multiple people.

As this system is relates so closely to reality, it makes some trade offs as far as what the system is capable of. Although it is more efficient to use an IDE for development, Tern chose reality over efficiency for a more hands-on programming experience. This allowed a novice programming to pick up a block and start programming, easily picking up programming concepts. As with efficiency, Tern’s versatility is limited by the same physical constraints that make it such a fluid interface.

Tern focuses on one task and accomplishes it through reality-based interaction techniques. The physical constraints and tangibles of the system promote a collaborative and intuitive interface while limiting the power of the system. Tern favors reality over efficiency and versatility in order to accomplish an interface perfect for novice programmers.