You could also think of this custom built mod as an "incomplete" Rhombic Dodecahedron.

• Inventor: Unknown
• Mechanism: 3x3x3
• Patents: Unknown
• Producer: Unknown
• Year: 1982
• Original Price: $0.00 USD
• Current Price: $51.72 USD

A standard Rhombic Dodecahedron has 12 sides. This puzzle has 18 because the 6 center cubies do not continue the planes of their four adjacent edge cubies to a point. Instead, the center cubies are flat, creating a new plane, but are stickered as those the planes were continuous. Each edge is the center of a hexagon. It could be viewed as truncated rhombic dodecahedron.
Apparently, this is not a custom-built puzzle. It was available in retail shops in exactly this shape, although there were some colour-placement variations.
The so far earliest known point in time this puzzle was mentioned was in Cubic Circular #3 by David Singmaster in 1982.

This puzzle is part of the series "Octgonal Edges". All modifications of this series are made by truncating an 3x3x3 on its edges. These truncations are symmetric as in the mass produced octagon from which the series takes its name.
The technical signature (Octagonal Edges 3A5E8A00145E97) indicates where to cut the original cube.
Without the keyword "Extended" it is a variant made only by truncating the original cube. With the word "Extended" some sides left over from the original receive additional extensions to "delete" some of these remaining faces.
The extended variant of this puzzle is the completed Rhombic Dodecahedron.

No later than 2012 another mass produced variant (under the name "Mask Cube") hit the market.

Price Tracking Data

DISCLAIMER: The following table contains user-generated content. This information is collected to serve as a rough guideline and is certainly not complete and may not even be accurate. This information is filtered and carefully moderated, but incorrect information will inevitably find its way into the system. Always use your own judgement when buying or selling an item.

	Sale Date	Price (USD)	Sale Type	Condition	Package Condition	Notes	Contributors	Edit
	Sep 8 2002	$79.58	eBay Auction	Average	Missing	None	Sandy
	Feb 17 2013	$5.50	eBay Auction	Good	Missing	None	Cubrick
	Oct 16 2003	$62.00	eBay Auction	Average	Missing	None	Sandy
	Sep 14 2003	$41.63	eBay Auction	Average	Missing	None	Sandy
	Jul 3 2003	$82.79	eBay Auction	Average	N/A	eBay.de.	Sandy
	Jul 28 2002	$38.85	eBay Auction	Average	N/A	eBay.de.	Sandy
= The sum of all currently check-marked rows.
= The average of all currently check-marked rows.

Thank you to the following people for their assistance in helping collect the information on this page: Sandy, Ton Dennenbroek, J. Spilsbury. If you have any information or images that you would like to contribute to this entry, please click the apropriate add () or edit () icon above, or use the following links to modify this item, add a recent sale price or to add a new link.