Initially, devices 10A and 10B of system 36 may be in an independent operating mode represented by state 50-1. In state 50-1, devices 10A and 10B are separated by an air gap and are not adjacent to each other. Sensors in components 38 can apply measured sensor signals to predetermined adjacency thresholds (adjacency criteria such as a minimum separation distance, sidewall alignment criteria, angular orientation criteria, etc.) to determine whether devices 10A and 10B are adjacent or are separated. When separated as shown in state 50-1, each device can operate independently. A single user may operate both devices or each device may be operated by a respective user.

Components 38 may monitor whether devices 10A and 10B are adjacent. Wireless communications (e.g., handshaking) between devices 10A and 10B to determine whether devices 10A and 10B are adjacent and/or other techniques for determining adjacency may also be used. In response to detecting that devices are adjacent, system 36 may transition to a joint (adjacent) operating mode, as illustrated by state 50-2 of FIG. 13.