Prism Pencils (pack of 85)

Photo of the pencil set, which comes with an instruction leaflet

A photo of the pencil set showing one of each type of pencil in the foreground (red, green and blue square pencils for the X, Y and Z axes, and yellow, cyan, magenta and black hexagonal pencils for the other four axes)

A photo of the rod packing structure made using these pencils, held up in Matt's hand. In the background you can see a simpler structure just made from the red/green/blue pencils; also in shot is a framed piece of brown paper from the Numberphile video about the Parker square, and a jar of dice.

Build your own rod packing structure! The set contains 45 square cross section pencils and 40 hexagon cross section pencils, which can either be built individually into two rod packing structures, or combined together into a superior 7-directional rod packing configuration.

Follow along using the video at mathsgear.co.uk/prism-pencil-instructions, or with Daniel Piker's manipulatable 3D model. Here's a paper explaining the mathematics of rod packing along cubic axes. When you've built your 7-directional model, here's what a sweep through the cross section would look like.

Elastic bands are not included. Pencils are unsharpened, and may optionally be sharpened to use as actual pencils.

Square section pencils: 15 Red, 15 Green, 15 Blue
Hexagonal section pencils: 10 Yellow, 10 Cyan, 10 Magenta, 10 black

Price = (the 357^th prime number) pence = 2399 pence = £23.99