The instructive case seems to be described as a type of adverbial case.....it is always in the plural, never takes a possessive ending, and is always construed in favour of the subject of the sentence..... However it seems to get more complicated than that....

...which leads to my question. These two sentences are examples of second infinitive nominalized verbs...
Juoksin laulaen.
Juoksin laulaessa.
Juoksin laulaessani....
Is there any material difference between the statements? I would translate the first two as: "I ran while singing," and the third, "I ran while I was singing." Is there a preferred way of saying this.... Or is it a matter of "six of one and half a dozen of another."....
