Tim shares a few more of his most unusual books.

First up, a Swiss book he bought about 20 years ago. The title on the front cover is almost invisible, unless you shake the book up and down, and then you see the title which is SEE. The book explores all kinds of optical illusions and tricks. Tim demonstrates a couple of examples of conical anamorphism.

A book with upside down pictures. Each image shows one picture, but when you rotate it either 90 degrees or 180 degrees, and you then see a completely different picture.

The next book is called CRAZY ART. Tim shows a photo of a landscape. Look more closely and you see that the whole scene is made from food - jacket potatoes in the background look like giant rocks, heads of broccoli look like trees, and so on.

HANIMALS is a book that contains pictures of the artists hands - hands which have been painted and decorated, so they resemble animals and other creatures!

Then a catalogue from the left handed shop in London.

CHOCOLATE NEWS is a magazine that contains nothing but stories about ... Chocolate. Sweet!

Finally, a book called THE BEST DESK TOYS EVER. Lots of lovely toys, just the sort of thing Tim collects!