There cannot yet be enough found edge pieces to complete the border, seemingly.   Perhaps a  half-dozen or so are lurking about among the others.  That would seem more likely than thinking they are missing.  Even though puzzle pieces have, like socks,  ways of migrating, have been found floating in the swim spa, in vacuum cleaner bags, on the backs of cats, in pockets, cuffs, heat vents, under cushions, and falling out of travel bags in distant cities, it is still too soon to tell.  Full precautions are in effect.  It IS the Tower of Babel. What can one expect?

About three-quarters of the border is installed, and already I have had to re-group, re-scrutinize, remove and replace the "pretenders." Those are the pieces that seem at first to fit, but do not, with the result that mysteriously, many other pieces that ought to fit in line have no place to fit. I call such a misplaced piece a "George Bush," and chant "Go home George Bush" when I find one and send it back to the equivalent of the oil-fields of Texas.  But it too has its final and unique place in the big picture.

The first puzzle piece shape I will describe I will call the "running man."  It might also be called a "ninja star" or even a "swastika" but each of those names appears less universal, less desirable.  To imagine the piece, start with a small square.  The piece is actually the smallest of all the puzzle forms.  We will need two other names useful in describing the pieces-- the interlocking parts.  Tabs and docks seem like a good place to start to describe the male and female parts.  This puzzle is a classic  "tab and dock" puzzle in fact, having no other weird shapes to account for.  To go back to the "running man" piece, it is only necessary to say that the middle of each side has a dock carved in it reaching three-quarters of the way to the center.  This makes the corners appear like ninja knife blades, or spear heads, or viper heads, but it also gives the shape of something designed to spin, which reminds me of the ancient symbol of the four legs and thus the "running man"  even if the legs are not bent at the knee. There was a former time, I believe,  that a swastika  was a folk good-luck symbol.  But that time is no more.