We have a family tradition: one particular jigsaw shall be brought out and completed once every bank holiday. The offending jigsaw is of a Celestial Planisphere, much like the illustration at the head of Wikipedia's page for Star Chart, except that the background is black with odd illustrations (the magnitude scale, a picture of the Local Cluster and so on). This makes it, ahem, challenging to work out if there's a piece misplaced, especially since the black started wearing off in the places where there would be visual clues. (My usual trick is to turn the pieces over to check for correctness of fit, but I've often thought of getting a light table.)

This year, we were five pieces known missing (all in the sky part), and seven I couldn't place in the available holes, when a decree went out from Herself that the dining room table shall be cleared for Christmas Day dinner. Now Herself has started on a present of a world atlas jigsaw, which may or may not displace the Planisphere in the tradition in question.

We now return you to the main thread.