Two parts are marked from different datums

A fictional joinery drawing specifies mating components from one reference face and edge. During marking, one worker measures the first component from the stated datum but the other from an unfinished opposite edge. Both individual measurements appear precise, yet the assembled joint is misaligned because the reference relationship differs. A colleague proposes forcing the joint together with larger clamps. Another checks the marking convention, actual dimensions and waste sides before accepting a correction. This written exercise cuts no timber and applies no clamp load. It asks why precision alone did not produce compatibility, identify the role of a common datum and avoid hiding an unresolved geometric error by forcing an assembly.