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The Trick


Case Study

Authors: Nina Dvorko, Thomas Endter, Martin Ruskov, Claudia Söller-Eckert, Nicolas Szilas, Paolo Petta

This case study is the result of a workshop with the title "Modelling a storyworld based on goals, tasks and obstacles" which was conducted during the Summerschool 2011 in Wiesbaden, Germany and was finally implemented in the EmoEmma system.



The story happens in a circus.

Characters and their backstories:

  • Sam, the cleaning boy:

    When he was still a baby, his parents died in an accident during one of their spectacular performances. They were high renowned tightrope acrobats, the main attraction of the Mirage circus at that time. The circus staff decided to adopt and take care of Sam until his fifteenth birthday, when he should decide how to take care of himself — likely leaving the circus. This important day is only a few weeks away now. While Sam is generally liked and appreciated in his activity as cleaner, his secret aspiration is to take centre stage of the arena, as assistant and future heir of the wizard Arkon.

  • Arkon, The Wizard:

    He wants to be the Lead Wizard of the Wizard World Organisation (WWO). Therefore he tries to develop a number of unique spectacular tricks. Nobody knows their secrets and their danger/price.

  • Konrad, the (speaking) mouse:

    The mouse was part of the acrobat session of Sam’s parents. That’s why Konrad has stayed closely connected to Sam ever since their accident.

  • Mr. Ed, the director:

    He wants of course some spectacular tricks, but he is basically a good guy.

  • Alice, the cat
  • Chip, the clown


Arkon is thinking about a new trick and preparing/trying out some possibilities. Konrad keeps him on close watch, because he suspects something. The WWO sponsors Arkon because he is famous and has now announced to have the “Best Trick ever”. The trick should again let people disappear. They will be burnt in a very spectacular way, but because of a special liquid they are not burnt (like for stunt men). But this liquid is not stable: when kept in stock for too long, it looses its key property and changes into the opposite, burning everything and also losing all its viscosity, starting to spread very easily.

Sam is cleaning the stalls of the elephants because he is very sensitive and the elephants require an empathetic person. But he suffers not to be centre-stage in the circus arena. He wants to be in the spots as well - like the Arkon, who is getting the most applause. Sometimes Sam is allowed to assist the Wizard - and then he is happy. Sam doesn’t know Arkon’s secret. Konrad gets angry whenever Sam helps the wizard, and tries to keep them apart. Sometimes Konrad even quarrels with Sam about that.

As Sam learns about the new big, big trick, he immediately wants to be part of it: in the short run, he hopes that through this demonstration of commitment and courage he will be ‘adopted’ for good by the Wizard and be able to stay with the circus, just in time before his fifteenth birthday. In the long run, he pictures himself as heir of Arkon’s glory. Sam thus wants to be one of the participants in the illusion, with the dangerous liquid spread on him.

At some point in the story, Sam or Konrad get to know about the dangerous trick


Sam wants to take part in the trick. The performance has already started! Konrad tries desperately to convince Sam and the director of the danger. Nobody believes him. Konrad is trying to buy time (e.g. by stealing the magic wand, making the clown extend his performance), so the liquid will start to smoke and thereby indicate that something is not in order.


  • Positive:

    In either case, a catastrophe is prevented!
    Sam knows a better trick to let people disappear: with the magic mirror and the help of his friends, the elephants and thereby Sam proves to be the better wizard and gets the award! Konrad is able to prevent the trick and the wizard is put to jail (or thrown out (or becomes another chance as advisor for Sam))

  • Negative:

    The circus burns…


The user plays Konrad.


The following figures are showing an example of the running story:

TheTrick01 TheTrick02 TheTrick03 TheTrick04
TheTrick05 TheTrick06 TheTrick07 TheTrick08
TheTrick09 TheTrick10 TheTrick11 TheTrick12

Creation Process

The Story “The Trick” was implemented both by the IDtension experts and the summer school’s participants, who had access to computers with a full version of the IDtension environment.

Overall process:

  1. General introduction into IDtension
  2. Hands-on IDtension Tutorial
  3. Story concept development
  4. Translation of Story concept into IDtension model
  5. Implementation of content material

  • Step 1: General introduction into IDtension

    This introduction was performed by the IDtension system creator in an informal way. First, all participants played with The Mutiny, the demo story of IDtension. A short discussion about their user experience followed. Second, the development environment was introduced, in particular the way to modify key authoring files.

  • Step 2: Hands-on IDtension Tutorial

    The tutorial is made of a series of successive interactive stories, which introduce progressively the concepts used in IDtension. Participants can see and modify the authoring data related to these stories, and observe the consequence on the user experience. The whole process is guided by the teacher who proposes some small exercises to be completed during the learning session.

  • Step 3: Story concept development

    Based on the various and rich ideas provided by the participants, data were progressively gathered regarding the characters, their motivations (goals), various events that could happen. These data were progressively grouped into related IDtension categories, in an informal manner. This step consisted in active group discussions, and was very iterative: characters were refined according to what could happen, what IDtension could perform, etc. At the end of this stage, a document was written grouping the characters’ description, backstories, and main storyline events. It is coarsely the story summary reported above.

  • Step 4: Translation of Story concept into IDtension model

    It consisted mainly in creating a “goal-task structures” for the story. This was achieved collaboratively, with various post-its used on a paper board. Different types, colors and orientation of post-its mean different structural elements (see opposite).


    In addition, information about characters, values, objects were put in other paper-boards (see below):

  • Step 5: Implementation of content material

    Several computers were available, and could access to the files of the story, thanks to a versioning system. Two main files were progressively written: the structure file and the expression file. In addition, the introduction text was also written. These authoring activities are difficult, and IDtension experts assisted authors. Note that a separation of tasks naturally emerged, some authors would write the structures (more demanding from a computing point of view), other would write the text expressions and the introduction. Continuous testing is necessary, to guarantee the correctness of structures and text in an iterative manner.

The picture below gives some impressions of the work.



by Dr. Radut.