A new and perhaps insoluble puzzle was appearing from the pieces of the old, but, where they bad been inchoate, this one would be finished and whole.

Bartok's own piano transcription of the Concerto for Orchestra offers insoluble puzzles, which the composer acknowledged.

Why he attempted it at all is an insoluble puzzle; under compulsion of what experience he attempted to express the inexpressibly horrible, we cannot ever know.

Kakuta put up a few welding seams in the airlock that will present them with an insoluble puzzle.

He remarks that, while the individual man is an insoluble puzzle, in the aggregate he becomes a mathematical certainty.

Do you laugh, reading that, or cry for the insoluble puzzle of being human?

Woman's heart and mind are insoluble puzzles to the male.

Fortunately I lack ears, so find hats an insoluble puzzle.

The insoluble puzzle is: who were the tribuni aerarii?

(My personal answer was to walk away - I could never solve the dilemma, but I personally hate insoluble puzzles.)