The Missing Area Paradox is very puzzling - people or objects seem to appear and disappear at will!
From Sam Lloyd's 1895 version, called the 'Get off the Earth Puzzle', which shows 12 warriors around the edge until you rotate the centre part, and suddenly there are 13! How did that happen? Tim then demonstrates a much more modern version, with a bird at the centre, surrounded by eggs and chicks. As you rotate the centre part, one of the eggs hatches. Finally a version with sailing ships.
Then Tim explores sliding versions of the same puzzle. He slightly miscounts on the chimneys puzzle - there are actually ten chimneys, and either nine or ten stockings, depending on where you position the slider. Then a version with sailing boats, where you can have ten, eleven or twelve. Then a very clever version, where sliding the two pieces of paper will give you either five or six faces. However in addition, it also shows their names, five names on one position, and six in the other position. When there are six faces, the names are all shorter - JOE, ROY, LEN are three of them. When you slide the pieces of paper to get five faces, the names are all slightly longer - JOEY, RONALD, ALLEN etc. Very clever indeed!
The next version involves rearranging the pieces of the puzzle, normally there are three pieces and you need to swap two of them, in order to get the 'other view'. From Harry Lange in Sweden, Tim shows the famous picture with the trolls - but are there three or four trolls? Then a clever version with six men and four glasses of beer - surely two people are going to miss out? But no, swap the top two pieces of the puzzle over, and now there are five men and five glasses of beer! Next, we have Alice in Wonderland, looking up at not one but five Cheshire Cats; however rearrange the top two pieces, and now there are only four Cheshire cats; but hang on... what's that in the middle? Ah, it is just the smile that is left from the vanished cat, just as the smile was the last thing to go in the original story by Lewis Carroll.
Tim explains that people knew about this kind of puzzle at least 250 years ago!
Next, a puzzle with three moving pieces. It shows a group of children on a trip in the mountains. Initially was can see that there are eight children. However rearrange the pieces and now one of the children has gone missing, there are only seven now. Oh dear...
Then another illusion or trick maybe from Sam Lloyd. The picture shows two horses, back to back. On a separate piece of paper there are two cowboys. You have to place the strip of paper so that the cowboys are sitting on their horses. Initially it looks impossible, but that is only because the solution is counter-intuitive. Tim shows us how it is done! And then another version with hands stroking cats.
Finally, Tim's pièce de résistance, a toy he only got very recently. It is a large ceramic ashtray, with a number of cigars balanced around the edge. But how many cigars are there? Is it six? Or maybe seven? No, I think there are eight! In fact, by rotating the centre part of the ashtray, you can have any of these options. Tim's magic cigars!!