The instructions tell you to cover a picture with the red Gelatine leaf and the picture will change to answer the question that is printed on the picture. The one illustrated shows some children. When the Gelatine is placed on top, the Giant becomes visible. Printed in Bavaria. D.R.G.M. 316414.

The disk should be placed on a flat surface and spun. When you stare at the centre for 15 seconds and then look away, whatever you look at begins to swirl in a most disconcerting way. The disk was invented by magician and optical illusion expert Jerry Andrus and produced by Binary Arts Corporation, Alexandria, VA 22314, USA. Copyright 1998 Binary Arts Corp.

The photograph cannot do justice to what you see when you view this bookmark. The silver spheres appear three dimensional and the red circle appears to be be below the actual level of the bookmark.

This is a fun application of a well known optical illusion. If you spin the disc clockwise on a table and look at its centre for around 20 seconds, and then look at the bunny sitting nearby, the bunny will appear to increase in size. Spinning the disc anti-clockwise will make the bunny look smaller. Made in China for Worldwide co, 3 Warple Way, London.

Inside the black dome are two parabolic mirrors which create a floating, 3D optical illusion of anything placed inside the Mirascope. The illusion is very powerful, although it is sensitive to angles. Made in China for TOBAR, Beccles, England. www.tobar.co.uk.