The last piece of the puzzle involves engaging people so that they fully commit continuously to achieving the plan.

FORBES: Why Engaging Your Employees Is The Answer To Strategic Planning

And that really might just be the last piece of the puzzle we need to build that desired space elevator.

FORBES: Is This The Final Technical Piece We Need For The Space Elevator?

The last piece of the puzzle was capital expenditures, and at what point companies would start investing in their core business.

FORBES: Good Buys In A Market With Room To Run

Then more recently, Kickstarter and Etsy and other markets that have basically solved the last piece of the puzzle, which is finance and distribution.

FORBES: Chris Anderson: How the Makers Will Create a New Industrial Revolution

One last piece of the puzzle, a substantial reduction in spending and tax benefits is likely to have a significant negative affect on our economy and Gross Domestic Product (GDP).

FORBES: Treating Federal Tax Benefits Like Budget Items: Where Can We Cut Tax Subsidies? Can This Be a Partial Solution to Sequestration?

The last piece of the psychological puzzle is the mental trap that a rogue trader finds himself in once the losses start stacking up and he faces an impending deadline at which point the game will be up.

BBC: The psychology of the rogue trader

Placing the last piece on the Underwater Realm puzzle, for instance, means the puzzle can be brought to life through another use of augmented reality.

BBC: Furby, aliens and jigsaws: Top toys get techy for Christmas