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This is an 8m by 6m room. The black circles are people. Each person has decided to follow two others in the room, indicated by the arrows.

The objective is to end up in a position where each person stands an equal distance from each of the two peple they are following.

Each person advances at the same time, each employing the same
strategy. In the picture, **T** is following **P** and **Q**. The dotted line
indicates all points equidistant from **P** and **Q**: that is, the line
through **M** (the midpoint of **P** and **Q**)
which is perpendicular to **P**Q. **T**
moves towards a point on this line, **Tâ€™**, which is the same distance
from **M** as **T**.

Each person contributes towards the displayed error. The error
contributed by **T** is the absolute difference between the lengths **TP**
and **TQ**, measured in millimetres.

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Source code for this page can be found at github.com/wordaligned/followme

For more context, see wordaligned.org/articles/follow-me-follow-me

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The button icons were downloaded from glyphicons.com and are licensed under the CC BY 3.0 terms.