Look for a similar solution and *copy* it to the new situation making
suitable substitutions where appropriate.

*E.g.* Geometry.

If you know about lengths of line segments and a proof that certain lines are equal (Fig. 29) then we can make similar assertions about angles.

**Fig. 29 Transformational Analogy Example**

- We know that lines
*RO*=*NY*and angles*AOB*=*COD* - We have seen that
*RO*+*ON*=*ON*+*NY*- additive rule. - So we can say that angles
*AOB*+*BOC*=*BOC*+*COD* - So by a transitive rule line
*RN*=*OY* - So similarly angle
*AOC*=*BOD*

Carbonell (1983) describes a *T-space* method to transform old solutions
into new ones.

- Whole solutions are viewed as states in a problem space -- the
*T-space*. -
*T-operators*prescribe methods of transforming existing solution states into new ones. - Reasoning by analogy becomes a search in T-space -- means-end analysis.

dave@cs.cf.ac.uk