Designs have a technical range, specified by the conditions that guide their development. Such analogical spatial moments in the technical give rise to the elementary applied linguistic concept of technical extension or continuity on both the norm side and factual side. Examples are the dimensionality and internal coherence of a designed intervention, since factual designs have parts positioned in relation to others in a coordinated whole. More broadly, their technical locality is worth considering in a fundamental analysis. The analysis seeks to uncover a fundamental design principle: recognizing and honoring the limitations and scope of applied linguistic designs. [For the complete volume, "A Theory of Applied Linguistics: ?magining and Disclosing the Meaning of Design. Educational Linguistics. Volume 65," see ED672528.]