How can a teacher introduce programming to an entire classroom of children with only one or two computers available?

Tangible programming languages can free programming from the computer screen and allow students to work on their own desks or on the floor.

Quetzal (pronounced ket-sal) is a tangible programming language designed for children and novice programmers to control LEGO MINDSTORMS robots. It consists of over one hundred interlocking tiles representing flow-of-control structures, actions, and data. Programmers arrange and connect these tiles to define algorithms which can include loops, branches, and concurrent execution.

Children carry their programs to a scanning station when they are ready to compile. The scanning station uses a commercial digital camera and reliable image processing techniques to convert physical programs into machine code.

• Reliable
• Inexpensive
• No embedded electronics or power supplies
• Useful in both online and offline settings
• Physical parts reinforce language syntax and semantics
• May facilitate collaboration between students
• Eliminates distraction of desktop computers

Based on initial usability sessions, we have formulated several high level questions that we hope to explore:

1. Are tangible languages a viable alternative to more traditional languages used in the classroom?
2. Do tangible languages offer increased opportunities for student learning?
3. Can tangible languages improve the style and tone of student collaboration?
4. Can tangible languages help teachers improve classroom management?

Individual Quetzal statements are imprinted with circular symbols called SpotCodes. The codes allow the compiler to quickly determine a statement.s type, position, and orientation.