Before Your Very Eyes!

A drum built around Hub Discs rotates at moderate speed on a vertical axle, powered via driving bands from a cube motor. It seems that the colour of the whole curved surface alternates every few turns between bright yellow and deep blue.

Can that rotating drum really change colour every so often? Or is my power of psychic suggestion putting weird impossibilities into your head?

The trick at the heart of the device is by no means original. There are card and paper versions dating back well over a century but I believe this to be the first Meccano version. And I have never seen this trick arranged all the way round a cylinder before.

My version is entirely Meccano (with my usual disclaimer about all those heretical washers). I hope everyone will try figuring it out for themselves, but there can be no touching and certainly no stopping the mechanism. If you manage to work it out, maybe keep it to yourself so as not to spoil the puzzle for others. I must decline to give clues how it works. Except for the story of the earliest Meccano Kemex outfits which were recalled to Binns Road due to ‘health and safety concerns’. I make no comment on the rumour about the Magic Circle discovering that each of those outfits contained a phial of Oofle dust (Kemex part K00f) and the Circle put an unspeakable curse on Frank Hornby until he ordered their recall.

It’s not as reliable as I’d like — each time it breaks down, I do what it can to prevent that particular failure and next time it somehow finds a new way to go wrong.


I see it but I simply can’t believe it.

An amazing model.

Your e-mail address will not be displayed in public and will not be added to mailing lists. Please see our privacy policy for further information.

Please wait while we post your message…