An Invitation: Gathering 4 Gardner Celebration of Mind 2016

We are excited to be once again hosting a fantastic day sharing interesting puzzles, maths, magic & science.

gathering-for-gardnerLetchworth Garden City, Hertfordshire photo

Saturday 22nd October



What is G4G?

Martin Gardner

Martin Gardner was an American writer who pioneered the field of recreational mathematics for many years. He died in 2010 and since then Gathering for Gardner (G4G) events have been held around the world, usually in October, to celebrate the types of pursuits he made popular. You can read more about these events at

The focus is on sharing interesting things in the related fields of:


  • mathematics,
  • science,
  • puzzles
  • & magic

What happens at the celebration?

The day will include a series of 5-10 minute talks as well as the chance to browse various tables of interesting objects with the opportunity to play with a wide variety of 3D puzzles and have a go at various mathematical puzzles. Attendees are encouraged to contribute to the display tables or to give a talk.

What will be there?

Activities and display tables are expected to include 3D puzzles; mathematical origami; optical illusions; 3D printing; mathematical conundrums; challenge games (eg rush hour). The 2016 talks will be listed soon. The C4G COM Letchworth 2015 talks included:

  • how to make impossible objectsoli bottles
  • easy way to understand Tower of Hanoi
  • how the Infinity puzzle was solved
  • automata
  • extreme puzzles
  • magic

Interested in attending? Please let us know and we will send you an invitation. Please then RSVP so that we can update our numbers. Also, let us know if you would like to give a talk or contribute to the activities and displays.


3D Printing Impossible Objects

img9When metagrobologist David Singmaster gave his talk on Impossible Grilles at MathsJam 2015, it inspired Simon to print some of these “impossible objects” using the THREEDY 3D Printer he happened to have to hand. puzzlegrill

Whilst travelling around medieval cities, particularly during Italian holidays, David observed the heavy grills over windows of buildings. Many years ago, he noticed that the bars at the centre formed a pattern which seemed to be impossible to assemble. This “impossible” grill pattern is also depicted in M.C. Escher’s Belvedere print.

David later saw that this central area could be assembled by a simultaneous converging process but the pattern continues and this made his idea fail. David showed his idea to James Dalgety, who proceeded to make an example from heavy wire; David then saw how to assemble the whole pattern easily.


The grill rods are printed individually, then slotted together – simple as that!

A belated thank you to David Singmaster for his inspiring talk.


Ambiguous Cylinders on the West Highland Way

Simon and his family enjoyed their summer holiday walking the West Highland Way – yes, all 96 miles of it. IMG_20160823_133906IMG_20160831_112800Greetings to the physicists from University of Munster, with whom we shared these Ambiguous Cylinders. The ambiguous cylinders were printed on a THREEDY 3D Printer, with kind permission from Kokichi Sugihara. This illusion was designed by Kokichi Sugihara and won second prize in the Best Illusion of the Year Contest 2016. More info (and other fantastic illusions) can be found on his website.


Interesting Variants on Tetrahedral Geometry

If you are lucky enough to have received some of our Tetrahedral Shapes and are looking to check your answers to the questions, you have come to the right place! Need more copies of the handout? Download a pdf here: Tetrahedral Geometry



What is the volume of the tetrahedron?

The whole cube with the corners on the 1,1,1 and -1,-1,-1 co-ordinates has a volume of 8 (2 x 2 x 2). The volume of the tetrahedron is 1/3 of this, ie 8/3

What is the volume of the triakis tetrahedron?

16/3 (this is exactly twice the volume of the tetrahedron)

How many cuts do you need to cut a rectangular block of cheese into three equal amounts using

a) a straight knife?  4

b) a cheese wire? 2

We hope you enjoyed the puzzles. If you would like any further explanation of the answers, please comment below.

The shapes were all printed by a THREEDY 3D Printer. If you would like to know more about THREEDY 3D printers, please browse our website. The printers are great for schools and colleges and we would be happy to visit you to demonstrate our printers, or deliver our 3D Printing workshop tailored to your students.

Please contact us to book a visit, or if you’d like any more information.

Trigantius Go Tournament

THREEDY 3D Printers is sponsoring Cambridge Go Society‘s annual Trigantius tournament tomorrow – you can expect that the prizes will include puzzles printed by our THREEDY 3D Printer!

Go is one of the world’s greago-boardt strategy board games. It originated over 3,000 years ago in China and is part of popular culture today in Japan, China and Korea. Whilst less well known in the west, you have probably seen AlphaGo in the news recently.

AlphaGo-Lee-Sedol-first-moveDeveloped by Google DeepMind, AlphaGo is the first computer programme to ever beat a professional player at Go. The 40th Trigantius Tournament is taking place in Cambridge this weekend, whilst the landmark five-match tournament continues in Seoul between AlphaGo and the best human Go player of the last decade – Lee Sedol.

Want to know more about Go? Visit the British Go Association’s website.




Social Media Ezi-gami Competition

Have you seen our Ezi-gami Shape on Facebook & Twitter?

NAME THIS SHAPE on either our Facebook & Twitter posts.

The winner will be drawn from the correct answers on Friday 4th December at 10 am and will receive an Ezi-gami modular oragami kit, with which they can make their own version of this shape.

This is made with 30 sheets of Ezi-gami™
This shape is made with 30 sheets of Ezi-gami™

Hint: the answer can be found within our website