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Workshop 2

In this workshop you will be introduced to Web Eden, an Empirical Modelling tool that enables you to create, observe, and experiment with computer-based artefacts. We shall be using the environment to continue our exploration of sudoku and to show you how colour sudoku was developed. Before embarking on the tasks below - which will be made available on Wednesday, you should first work through the introduction to Web Eden and the EM Sudoku model at The links for Task 1 and Task 2 are currenty available: the link for Task 3 will be made available shortly. 

Task 1: Introducing the EM Sudoku model

We continue our study of Web Eden by loading a Sudoku model. The model itself is built up out of several thousand small definitions, rather like the definitions in the cells of a spreadsheet. The various notations used in constructing the model will be illustrated by extracting small components of the model, as captured by subsets of definitions, and playing with them in an exploratory fashion. For the most part, the emphasis will be on giving you simple examples of redefinitions you can make and new definitions you can introduce that you can then adapt and experiment with. This is intended to give you a better understanding of key concepts of Empirical Modelling, especially that of a dependency. You can find the link to this task at

Task 2: First steps in Empirical Modelling

In Task 1 you will be imitating and modifying given definitions. In this task, you will have the opportunity to frame new definitions of your own. These will be designed to give you some very basic skills in the use of Web Eden that are sufficient to build simple models of your own. They will also enable you to appreciate some of the basic steps that were involved in the construction of the Sudoku model - an activity that has involved sporadic input from several modellers over a period of more than three years. You can find the link to this task at

Task 3: Building colour sudoku

 This task will introduce you to definitions that transform an ordinary Sudoku model into a Colour Sudoku model. The colour sudoku model that we have built within the Web Eden environment was the inspiration for the colour sudoku program that you used in Workshop 1. The Web Eden model is much more flexible and extensible than the program - but not so suitable for general distribution! To help you appreciate the different character of the Web Eden colour sudoku model, you will be introduced to the underlying definitions that determine the colours of cells. You will also be invited to propose - and implement - alternative colour blending strategies of your own. You can find the link to this task at


On completing Workshop 2, please go to the Feedback 2 page to send your answers and comments to us.