Imagine that someone has just dumped a 1000-piece jigsaw puzzle on a table in front of you – a large pile of unintelligible puzzle pieces – but you cannot see the box cover.
(And for those who are experienced at working jigsaw puzzles, to make things even tougher imagine that the puzzle appears to have no distinct edges…)
Where do you begin? Without a clear understanding of what the puzzle is supposed to look like, it will be very tough to complete it.
Imagine being presented a demo delivered the same way – lots of individual pieces but no clear picture of the end result…
On the other hand, if you are shown a picture of the completed puzzle up-front, then you have a reasonable possibility of working the puzzle. Similarly, it you are shown the end result of a demo at the beginning, then you have an understanding of how the various pieces contribute to the end deliverable.
A jigsaw puzzle is a wonderful example of a Great Demo! before-and-after Illustration in practice. The “before” is the image of the pile of confusing puzzle pieces; the “after” is the picture of the completed puzzle.