Coming back briefly to nominal compounds of form N N, note that unlike conventional compounds such as ice bucket or ice sculpture—ones approachable using an enriched lexicon, heuristic rules, or statistical techniques—some compounds can acquire a variety of meanings as a function of context. For example, rabbit guy could refer to entirely different things in a story about a fellow wearing a rabbit suit, or one about a rabbit breeder, or one about large intelligent leporids from outer space. Such examples reveal certain parallels between compound nominal interpretation and anaphora resolution: At least in the more difficult cases, N N interpretation depends on previously seen material, and on having understood crucial aspects of that previous material (in the current example, the concepts of wearing a rabbit suit, being a breeder of rabbits, or being a rabbit-like creature). In other words N N interpretation, like anaphora resolution, is ultimately knowledge-dependent, whether that knowledge comes from prior text, or from a preexisting store of background knowledge. A strong version of this view is seen in the work of Fan et al. (2009), where it is assumed that in technical contexts, even many seemingly conventional compounds require knowledge-based elaboration. For example, in a chemistry context, HCL solution is assumed to require elaboration into something like: solution whose base is a chemical whose basic structural constituents are HCL molecules. Algorithms are provided (and tested empirically) that search for a relational path (subject to certain general constraints) from the modified N to the modifying N, selecting such a relational path as the meaning of the N N compound. As the authors note, this is essentially a spreading-activation algorithm, and they suggest more general application of this method  (see section 5.3 on integrated interpretive methods).