Informatrix — Learn Information Theory through Fun!

EE376A (Winter 2019)

By Jack Jin, Yueyang Liu, and Kailai Xu

Love board game? Want to learn information theory? Then this might be the right post for you. In this post, we introduce a new board game that assists you learn information theory through fun — Informatrix.

— A game of information

The game allows 2-6 people playing at the same time and is appropriate for people from 6 years old. It usually takes 30 minutes for a single game.

The game is inspired by Chinese checkers and Catan. In this game, every player starts with 5-10 information sources, and tries to transmit the sources through the channels. For each player, there are assigned destinations for the sources. The first player who has successfully transmitted all the sources to the destination wins the game. The process simulates the process of information transmission in real life. Your information sources are not safe all the time in the noisy channels. So be ready to route your information sources with your intelligence!

The board of Informatrix. Each polygon (4, 6, or 12) contains one of the three resources, noise, or a random resource. The channels are the lines of the polygon and the intersections are the relays Each relay is affected by the (at most) three adjacent polygons.

As you can see in the board, the channels are populated with different resource: copper, plastic and silicon. They are essential blocks for building up the communication system. We also have several noisy sinks. Each round, the players move one of their sources one step forward; then a dice is tossed to decide the active noisy sink and the active channels. The information source on the edge of the sink will be corrupted and put back to the starting point; the players will acquire the corresponding resources if they have sources on the edge of the active channels.

The three resources available in the game.

The players can use the resources to purchase correction code. The price of one correction code is 6 copper + 3 silicon + 1 plastic. When one of the player’s sources is corrupted, she can pay one correction code to immunize the source from corruption. Players can also purchase compression at the price of 1 silicon, allowing the player to move her information bits twice in the current turn. The most fun part is that the players can trade resources and correction codes with one another at any price they agree on.

We also mimic congestion in information theory by disallowing two sources occupying the same location. The players can negotiate with each other or reroute their information.

That’s all! Simple enough but covers many basic concepts in information theory. It basically teaches the players how information is transmitted and how they are impacted by the noise and congestions in the channels. Also the concept of correction codes is very important and we make the codes incentives for players to collect the resources.

Outreach Activity

As for our outreach event at Nixon Elementary school, we designed a session where we have the kids read flashcards on information theory and answer short questions. A list of the topics on the flashcards are:  

  • Background of Claude Elwood Shannon​ and his 1948 paper “A Mathematical Theory of Communication”. 
  • A typical structure of a communication system. 
A communication System
  • Examples of a noiseless channel, a binary symmetric channel, etc. 
  • Code, and ASCII and DNA as examples. 
  • The concept of entropy and an example of Morse code. 
  • Mutual information. An example that illustrates the concept is presented below: You walk outside at night and found out that the grass was wet. You then deduce that it must have either rained, or the sprinkler must have been turned on. Thus, Rain and Sprinkler have mutual information!​
An illustration of mutual information
  • Huffman Code. Background of Claude Elwood Shannon​ and his 1948 paper “A Mathematical Theory of Communication”. 
  • A typical structure of a communication system. 

Below is a photo of the poster (of eight flashcards) we had in the outreach event:

A photo of the posters at the outreach event. We forgot to take one during the event, so we cropped this out from a group photo taken at our booth.

We’ve learned a lot during the outreach event explaining basic concepts in information theory to 1st to 5th graders. The older kids were able to grasps the concepts, while to some younger kids we had to explain using the words they understand. A 1st grader asked questions like “what does the word ‘structure’ mean”. We find it easier to communicate the ideas to them when a younger kid comes with his or her older sibling, as they can discuss their understandings.

The outreach event is overall a fun experience, and both the kids and us have enjoyed it. We give the kids both pencils as and flashcards with information theory concepts on them — so that they could review it after the outreach event — as prizes. We’ve distributed more than 70 copies of flashcards.

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