Wearable devices

A geofencing system comprising:

• at least one physical, moveable marker, the or each marker being arranged to define at least part of a geofence based on the position of the moveable marker such that changing the position of the or each moveable marker changes the geofence, and wherein the or each marker is arranged to be human-portable by an individual for allowing the person to pick up and carry the marker and provide a visible and/or audible indication of the geofence, and the or each marker is arranged to indicate the presence of the geofence and the shape of the geofence;
• and
• at least one wearable device arranged to receive data concerning the position of the geofence,
• and wherein the wearable device is arranged to store geofence information and to provide an alert in response to the wearable device crossing the geofence;
• wherein the or each marker indicates a direction in which the geofence extends therefrom;
• wherein the system comprises a plurality of markers, and wherein the markers define corners of a polygonal geofence;
• wherein the or each wearable device is arranged to listen at set times to receive updates to the geofence information resulting from movement of one or more of the markers;
• wherein the at least one wearable device is arranged to provide data on a position of the wearable device to the marker and the marker is arranged to log position data of the at least one wearable device.