A jigsaw puzzle.
Something that can be compared to a jigsaw puzzle.
A power saw with fine teeth and a narrow blade which can cut curves in wood or metal.
To cut something using a jigsaw.
A problem that is challenging to solve.
A situation, person, group, etc. which is difficult to deal with.
A place, opportunity, etc. to which it is difficult to gain entry.
An amount that is difficult to finance.