In this exercise, your aim will be to model a simple real-world story by making use of a construal. The construal will be a blend of two construals that you studied in previous sessions: the electrical circuit construal made by Elizabeth Hudnott and the light-in-the-room construal made by Ilkka Jormanainen. Your model will consist of a sequence of 'real-world' events and actions that you describe by appropriate interactions with the construal, appropriately interpreted. The most important aspect of this exercise is not the technical content, which (once you understand what you are doing) is quite simple - it is the thinking about the scenario that making the construal provokes.

Anna is a physics teacher who lives in a small flat in Athens. It has two rooms, a living room and a bathroom. One evening, she comes home from attending a CONSTRUIT! training course to find that the light in her bathroom doesn't come on. It's a pull-cord switch, and she pulls the cord to click it 'on-and-off' in case the switch has got stuck, which it sometimes does, but nothing happens. Anna knows that the light in the living room is working. She is very safety conscious and won't remove the bulb unless she is sure that it is safe. But now she doesn't know whether the bathroom is switched on or not.

Anna knows the electrical circuit in her flat - coincidentally it is as the circuit that was described in the EC construal presented in the course organised by CONSTRUIT!! She knows that it will be safe to change the bulb if she first turns off the master switch. So she [finds a new bulb, a torch and places a chair where she can stand on it to change the bulb, then] switches off the master switch and changes the bulb.

Can you make a blend of the electrical circuit (EC) and light-in-the-room construals (LIR) together with a sequence of definitions of observables that reflect the real-world scenario and Anna's thought processes?

Here are some hints and key questions that you will need to consider:

The most appropriate way to blend the construals is to use the LIR construal to represent the actual state of the bathroom light and switch as observed by Anna, and to use the EC construal to capture her mental model of this state.

Technically, you create the blend by loading both construals one after the other. The only observable common to both construals is the 'picture' observable. In order to have both pictures on the screen, you proceed as follows: First load the EC construal, then load the LIR construal. Execute the following code:

createCanvas("circuit");

Focus first on the real-world scenario as represented by the LIR construal. You will model what Anna actually observes, and how she acts in terms of interactions and interpretations of the LIR construal. You should consider how to model the fact that:

• the bulb in the bathroom is broken
• Anna doesn't know whether the bathroom light switch is on or off
• the Y/N question to which Anna seeks the answer is is it safe to change the bulb?

To model what Anna does and sees, you will need to change some definitions that relate e.g. to the text on the switch, the Y/N question and the status of the light switch. Can you add a real-world counterpart of the master switch to the LIR construal?

When you have set up the LIR construal, you can consider the EC construal. The role of the EC construal is to model what Anna imagines is going on when she interacts in the real-world scenario. Some questions to consider:

• How would Anna's action in switching the actual master-switch off and on be reflected in the EC construal?
• The first state changing action that Anna takes is to switch the bathroom lightswitch from 'on' and 'off' or vice versa, though she doesn't know which. How is this state-change reflected in Anna's mental model of the light circuit? What simple definition to connect the two construals can be introduced to model this?
• Does it matter that both bulb components 'light up' even though the actual bulb isn't lit? In what context might it be appropriate for neither of the bulb components to light up?

When you have configured the blended construal suitably, taking account of the above points:

• Play out the the story line spelled out in the passage above by walking through the changes of state through redefining observables / interacting with the blended construal.
• Act out some alternative scenarios, such as Anna unfortunately making an invalid Y/N guess about the status of the circuit and getting electrocuted, or the dilemma that would be faced by Anna should she come home to find that neither light is working (have both bulbs failed, or is there an electrical power cut?).
• Consider how you might extend the construal to model the situation in which Anna has an electronic testing device that enables her to test whether the switch is on or off without removing the bulb.