Abstract
Algorithmic thinking is at the heart of computational thinking: it requires to abstract a problem and to model it, as well as to specify a sequence of instructions for solving it, that is, an algorithm. In many countries, computer science education in primary or secondary schools is moving towards computational thinking and, partly, algorithmic thinking education. This paper supports the idea that algorithmic thinking should be taught from primary schools, through physical activities, without sitting in front of a computer screen, and by exploiting Internet of Things technologies, specifically, by using inter-connected interactive tangible objects. The paper focuses on the design of such tangibles for teaching graph algorithmic thinking. It shows in what sense their design was participatory and followed an action-based re- search approach, moving from the context of use analysis to iterative design sessions and field studies with tangible prototypes, used by teachers or children. The paper presents one of such tangibles and field studies with children. The paper ends by reflecting on the design process of tangibles for graph algorithmic thinking.