# Shardinaires-9™

## Introduction

Shardinaires-9™ is Kadon
Enterprises' set of nine puzzle pieces
for making geometric and naturalistic shapes.
The name refers to the shapes, which resemble shards of glass.

These pieces belong to a class of *hybrid* polyforms,
or *multi-polyforms,*
geometric shapes formed by joining two or more kinds of basic cells.
For Shardinaires-9, these cells are the *monomino* and the
*monodom*:

Doug Caine has named such polyforms *polyshards,*
because they are generalized Shardinaires-9 pieces.

## Pentominoes and Tetrominoes

A *tetromino* is a plane figure formed by joining 4 equal squares
edge to edge.
There are five different tetrominoes:

The diagram above shows seven tetrominoes.
This is because two of the five have been flipped over
so as to occupy different
positions on the square grid. They have different solutions.

There are 12 different pentominoes:

The first challenge for Shardinaires-9 is to arrange the 9 pieces
to form every pentomino and every tetromino.

Another challenge is to
form some polyominoes by using fewer than 9 pieces.

## Other Challenges

Shardinaires-9 can also be used to form various convex shapes,
symmetric shapes, and congruent or similar groups of shapes.
They can form letters and numerals.
They can also form art shapes like this Running Man by Kate Jones:

The instruction booklet for Shardinaires-9 is here.
You can buy copies of Shardinaires-9
here.

In 2019, Kadon awarded Shardinaires-9 its GAPE (Gamepuzzles Annual
Pentomino Excellence) Award.

## History

Shardinaires-9 was inspired by Donald Bell's
**Loyd Polyominoes.**
Donald named them after this 4-piece dissection by Sam Loyd:

Donald sought a minimal set of pieces that could form every pentomino and
every tetromino.
The problem had been studied before, but not systematically.
Donald used computer analysis to search for sets of pieces.
The Loyd Polyominoes, a set of 8 pieces, were the result.

Acrylic sets of Loyd Polyominoes, made by Dave Janelle of Creative Crafthouse,
were Donald's exchange gift at Gathering for Gardner 13 in 2018.

After Donald told me of his work, I joined the search, using software of my
own.
I found several sets of pieces that Donald had not found.
Two of them had nine pieces, all different!

About a month after Gathering for Gardner 13,
Kate Jones of Gamepuzzles.com
found her gift set of Loyd Polyominoes.
She and I discussed the set and its variants.
In the end, Kate decided to manufacture one of my sets of 9 different pieces.
She named it Shardinaires-9.

For months afterward, we developed new challenges for
Shardinaires-9.
When we had found enough, Kate wrote a booklet of them and began producing
Shardinaires-9 for the retail market.

Col. George Sicherman
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