Tern: Wooden blocks shaped like jigsaw puzzle pieces
Created by Michael Horn and Robert J.K. Jacob at Tufts University, Tern is a tangible programming language for middle school and late elementary school students. Children connect the tailored wooden blocks to form physical computer programs, which may include action commands, loops, branches, and subroutines.
Download Tern's paper for Chi'07
Prior to designing Tern, the authors created Quetzal (pronounced ket-sal), 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."
Also Oren Zuckerman from the MIT Media Lab created Systems Thinking Blocks for children to model and simulate dynamic systems.
Flow Blocks for children "to create 3D structures in space, that look like common structures in life"