Itchmap

Primary Actors: Itchy(Alice), Scratchor(Bob)

Scope: 2 (or more) individuals in physical proximity sharing the goal of itch-relief in one party, by localised application of finger-based epidermal abrasion by the other.

Story: Alice has an itchy back, she requests that Bob scratches it and Bob agrees. They enter into an iterative feedback loop where Bob's scratching is applied to an area of Alice's back and Alice directs Bob using a mixed protocol of verbal and physical cues as to the relative location of the itch and its subsequent relief.
Often, the perceived location of the itch will develop during the scratching process and migrate to one or more sites on Alice's back.

Problem Statement: The verbal nature of the feedback protocol requires developing a shared simulacrum of Alice's physical sensation. The complexity of providing this information in a series of temporally separated commands can provide challenges;
"No, *my* left!"
"Up a bit, down a bit, no too far!"
"Yeah, just there! No! You missed a bit!"
Furthermore, such verbal communication requires a suitable atmosphere in which to function - underwater environments are, for example excluded from hosting such interpersonal interactions.

Solution: A small chip is inserted into Alice's brain at birth and hooked into the part of the brain onto which is mapped the sensory signals from her skin.
At the same time, she also receives 4 referencing tattoos, one at the nape of the neck, another two over left and right shoulder-blades, and a final one over the n'th vertebrae at the base of the spine.
A camera is pointed at Alice's back, and machine-vision software run to pick up the reference points. Initial calibration might be applied to ensure the software has Alice "the right way up".
The chip sends this information out to a device that projects a colour-map directly onto Alice's back highlighting (in red for example) the particularly itchy bits.
Bob simply scratches at the locations identified by the device in harmonious silence (not withstanding Alice's contented vocalisations).