I think a usage of daal which requires a little schematization is seen in the noun phrases lain-daal, or rekhaa-daal (both, meaning `the line'), or suli-daal (the hair). Here, we clearly see that the classifier daal is used with a purely geometric line---rigid or flexible. In other words, it is felicitous with an entity which is linear and long. This usage does not completely satisfy the ideal meaning we noted earlier because a line has no width. This may be taken as an evidence that the ideal meaning should actually emphasize the predominantly one-dimensionality of the object as the selectional restriction for the use of the classifier daal as in daal-daal (the branch).
A not-so-ideal usage of this classifier can be seen in the following: gas-daal (the tree), daal-daal (the branch), etc. In both these cases, there is abstraction and idealization. For example, the tree may have a lot of branches with or without leaves. There may be birds nesting in the leaves, etc. All of these become irrelevant when we say gas-daal. Somehow, the speaker idealizes the tree to its trunk which is solid, round and long, and as a result uses the classifier daal. Similar arguments can be made for the use of the classifier daal with the noun daal meaning the branch of a tree.
A special kind of schematization is seen when we use the classifier
daal with the word spring
as in
spring-daal. It shows a kind
of idealization which is pretty sophisticated, geometrically
speaking. A spring is
made up of a sequence of coils of some flexible wire-like object, usually
metallic. It has a principal longitudinal axis. Around this axis,
we can think of it as having a three-dimensional envelope which is
tubular in shape.
In addition, this enveloping tube, which can change in dimension, is
long at least in its extended form when a force is applied to the spring.
This tube is mostly empty space. But, the fact that we can think of it as
a tube with length facilitates the use of the classifier daal.