Separable assembly

A separable assembly comprising:

• a cellulose member having a side surface and an end face forming an edge with the side surface, the cellulose member defining an elongated sliding track therein, the elongated sliding track extending from an end opening at the end face and being of T-shaped transverse cross-section, the cellulose member defining a side opening along the sliding track at the side surface of the cellulose member, the sliding track further defining a detent recess spaced from the end face and extending into the cellulose member;
• and
• a rigid plastic member having an edge configured to be received within the end opening of the cellulose member and slid along the sliding track with the plastic member extending through the side opening, the plastic member comprising a detent protrusion configured to engage the detent recess to retain the plastic member at an assembled position along the sliding track,
• wherein the plastic member comprises a spring bridge extending between two fixed bridge ends spaced apart along the edge, with the detent protrusion extending from the spring bridge at a position between the two bridge ends, the detent protrusion and detent recess being configured such that sufficient force applied to move the plastic member along the sliding track from the assembled position toward the end opening will resiliently deflect the spring bridge to withdraw the detent protrusion from the detent recess.