The goal of this option is to enhance an existing space and the activities that happen within it, not to create an entirely new space. Your work be designed for the space you choose.

Phase 1

Choose a space in which there is a reasonable amount of activity. Why do people use the space, and what do they use it for? Observe an activity that happens there. Use pictures, videos, sound recordings, drawings, and any other form you need to in order to describe space and the activity. Look for patterns in the activity. Identify how the space and the activity are linked. Decide how you can sense the action and create a reactive or interactive system to enhance or change the activity.

Phase 2

Build a system to realize the change or enhancement you came up with. Find ways to use the space as it exists, rather than modifying it, unless it's absolutely necessary. Your goal should be to make a system that is as dependent on the location it's in, and uses it as well as, the activities you've observed.

As a passive example, you could sense how many people use each entrance to a given subway station, and how frequently. As a more active example, you might want to give people a surprise in their daily transit through a public square or lobby. In order to surprise them, first you'd have to observe and collect data on what the normal pattern of activity is, then make an output system that changes that pattern. Perhaps you want to make a sculpture that changes the patterns of pigeons in a public square (a la Ed Bringas). Or perhaps you just want to sense how long people use the bathroom, and tell them when they've been in there too long.

You don't have to limit yourself to sensing human activity. Perhaps you want to turn on the lights when it gets dark, or close the windows when it rains, or make a monkey dance when the sun is shining.

The activity sensed and the viewer observing the results can be two different people, species, etc. In other words, you don't have to close the interactive loop between the actor you're sensing and the viewer you're presenting the results to.

Phase 3

Document your system in action, and take notes on how well your system brought about the change or enhancement you intended. Observe how the system is misinterpreted by those it senses, if people are involved, or where it fails to sense the environment, if not. Come up with ways in which you could change the system to better realize your vision. Make those changes and try your system again.

Option 2: Device, Instrument, Tool

In option 1, the focus is on the activity of a given space. The activity might involve a large number of people to produce a greater result. In this option, the focus is on the activity, which may be independent of the space. The activity most likely involves a smaller number of people, or an individual.

Phase 1

Choose an action that produces changes in a medium. It might be strumming a guitar (the medium is sound), hammering a nail (the media are wood, nails, and sound), flying a model plane (the media are the plane and the air). What tool or device is the action taken on? What is the goal of the activity? Observe a person or people engaged in the activity. What are the physical parameters of that activity? What does the person engaged in it do with their arms, their legs, their hands or feet, their head? How do they change their posture? Where do they need to focus their attention? Is there a secondary focus of attention (for example, if two limbs are used independently)? What physical elements of the activity make it engaging? What elements make it difficult, painful, or boring?

Do the action multiple times (perhaps 100 times), or have someone else do it. Record the action, with a video camera, or sensors feeding a graphing program, or in some other way. What patterns appear when the action is repeated?

What are the physical characteristics of the medium that you have to take as given? What physical input to the tool or device suggest or mirror those characteristics? For example, how actions you take on an audio mixer mirror the inherent characteristics of sound?

Phase 2

Now that you've observed one tool or device that manipulates the medium you observed, create another one. Either modify an existing device so that it affords changes to the medium that it didn't previously, or make a whole new tool to manipulate the medium in new ways.

Ask yourself (and your intended users) why someone should use your device to do the job. Don't assume that someone will want to use it, or even know how to use it. Make the functions apparent, and figure out what will make a person want to use your device. How will it make their experience of the activity better?

Is your device dependent on other devices, or on a specific location, or on the arrangement of elements in a space? Where is is best used? What social situations (i.e in private, in front of an audience, in a crowd) are best for its use? How will you ensure that those conditions are met?

Phase 3

Get other people to use your device, instrument or tool. Try as much as possible to tell them only what they need to get started. For example, if you made a musical instrument, just tell them how to produce changing tones; don't tell them what to play. If you made a device that writes text in response to eye movements, don't tell them what to write, just tell them how to make letters. Observe how your users use your device. Take notes on where they defy your assumptions as to how the tool is to be used. Ask them how they think the device works (their mental model of the action). Listen to what they have to say, and figure out where their mental model diverges from your model of how it works. Use this information to make the tool better.