Apparatus and associated methods relate to an access control system having a planar interlocking mechanism including two reflectively symmetric rotating moon gears mechanically coupled by a linear slide configured to respond to rotation of the moon gears. In an illustrative example, the moon gears are mechanically coupled by the linear slide via respective actuating cams. The moon gears may be provided, for example, with locking cams configured to releasably secure the linear slide via a corresponding follower on the linear slide. Rotation of one moon gear into a first mode may, for example, place the other moon gear in a second mode, and vice versa. Each moon gear may be configured, for example, to be operated by a removable peg. Various embodiments may advantageously be configured such that release of a removable peg from one moon gear captures a peg in a corresponding moon gear.
