Minimal Spanning Trees

Networks are everywhere in modern society: roads, wires, water and gas pipes all connect one place to another. Computers are built of networks at many levels, from the microscopic connections between transistors in a chip to the cables and satellites that link the internet around the world. People who build networks often need to work out the most efficient way to make connections, which can be a difficult problem.

This puzzle shows students the decisions involved in linking a network between houses in a muddy city. It can lead on to a discussion of minimal spanning tree algorithms for optimizing networks.

Paving Stones

Activity description (PDF)

Translations and other Versions:

Related Resources

  • An older version of this activity can be downloaded in PDF format here. The content is similar to the current version, but there’s some extra technical information.

Curriculum Links

Great Principles of Computer Science [info]
  • Computation, Coordination
ACM K12 Curriculum [info]
  • Level I (Grades 3–-5) Topic 11: develop a simple understanding of an algorithm
New Zealand Curriculum [info]
    • Mathematics Level 1: Position and Orientation
      • Give and follow instructions for movement that involve distances, directions, and half or quarter turns
    • Mathematics Level 2: Position and orientation
      • Create and use simple maps to show position and direction.
  • Technology Level 1: Planning for Practice
    • Outline a general plan to support the development of an outcome, identifying appropriate steps and resources