Dan Hoey
Keith F. Lynch
I am as you may guess dreadfully sorry to report that Dan Hoey is
dead, and by his own hand. He committed suicide on 31 August.
The police found him in the bath, dead, with blood all over the
bathroom. I have been trying to locate people who knew him. His
two sisters and I are planning a memorial service, also an obituary
in the Washington Post. So much to do, and such a sad business.
We will keep you informed.
Dan was an occasional poster here in the rec.arts.sf.fandom newsgroup
starting in 1992. His last post here was just 26 days ago.
He was a PRSFS member and meeting host, having last hosted the July
meeting. He was the only host to live in DC proper. I learned of his
death when a member received a phone call during last night's meeting
and announced it to the group.
In the '80s and '90s he was a WSFA member. In 1995 he chaired
Disclave, the DC area's premier con from 1950 through 1997.
He was a Wikipedia contributor from 2005 until last month. In his
Wikipedia user page he describes himself:
I'm Dan Hoey, a mathematician, programmer, computer science
researcher, science fiction fan, and wise guy. In 2005-2006, my
Wiki contributions were mostly to Combinatorial game theory, but now
I've decided to be a combinatorial games theorist and so I'll mostly
recuse myself from that fray.
He was a contributor to open source projects.
He had at least one cat in his apartment in DC. I wonder what will
become of it.
I had no idea he was considering suicide.
I will miss him.
--
Keith F. Lynch - http://keithlynch.net/
Please see http://keithlynch.net/email.html before emailing me.
karl.j...@gmail.com
> Anne Hoey wrote:
>
> I am as you may guess dreadfully sorry to report that Dan Hoey is
> dead, and by his own hand. He committed suicide on 31 August.
Sad news. I think that there are some things that are worse than
suicide. I'm sorry he thought that's what he was facing.
Karl Johanson
Kip Williams
moved out of the area.
Kip W
Morris Keesan
conventions. Am I right in thinking that it was Dan who used to carry
around a tartan Rubik's cube?
--
Morris Keesan -- mke...@post.harvard.edu
Keith F. Lynch
> Am I right in thinking that it was Dan who used to carry around a
> tartan Rubik's cube?
including Rubik's Cube. He had several cubes and similar puzzles
at his apartment in DC at which PRSFS regularly met, most recently
in July. I don't recall if one of them was tartan.
Unlike me, he apparently followed the old etiquette rule that your
shelves should be 1/3 full of books, 1/3 full of other stuff (such as
geometric puzzles), and 1/3 empty. Cat-sized holes were cut between
the empty parts so that his cat(s) could explore and could reach the
upper shelves.
Keith F. Lynch
From: Monica McAbee
On behalf of Anne Hoey <Annehoey at aol.com> -
Anne would like any info about Dan's activities in fandom. Please
spread the word - and reply to her email, not mine. Thanks everyone.
Monica
Keith F. Lynch
pm in a home in Kensington, Maryland, which is near Washington DC.
If you wish to attend, please RSVP danhoey...@gmail.com.
Keith F. Lynch
> I didn't know Dan well, but I always enjoyed chatting with him at
> conventions. Am I right in thinking that it was Dan who used to
> carry around a tartan Rubik's cube?
Revised answer: Yes. Here are two messages from him on the topic.
Note that the second message involves fandom. As I just mentioned
in another thread, these messages, and hundreds more, can be found at
http://KeithLynch.net/DanHoey/
---
Date: Mon, 16 Feb 81 23:27:00 -0500 (EST)
From: Dan Hoey <Hoey@CMU-10A>
To: Cube Lovers
Subject: Four colors suffice
Douglas Hofstadter, in the Metamagical Themas column in Scientific
American this month, shows two alternate ways of coloring a cube.
Both suffer from two drawbacks: They fail to distinguish all cube
positions, and they use more than six colors. This seems inefficient
to us, since there is a coloring of the cube which distinguishes
all elements of the Supergroup and uses only four colors (and which,
like Hofstadter's colorings and the standard coloring, satisfies the
restriction that every whole-cube move is a color permutation, as
discussed in point 2 below).
Our coloring, called the Tartan, is formed by assigning the colors
blue, green, red, and yellow to the four pairs of antipodal corners
of the cube. Thus for each face of the cube, the four corners of the
face are assigned four different colors. We use the term ``plaid'' to
denote such an assignment of colors to the corners of a square. To
color the cube, divide each facelet of each cubie into four squares,
and color the squares so all facelets on a side of the cube display
the plaid associated with that face. The result is shown below, with
the initial assignment of colors to corners in lower case.
(r)---------------(y)
| R Y R Y R Y |
| B G B G B G |
| |
| R Y R Y R Y |
| B G B G B G |
| |
| R Y R Y R Y |
| B G B G B G |
(r)---------------(b)---------------(g)---------------(y)
| R B R B R B | B G B G B G | G Y G Y G Y |
| G Y G Y G Y | Y R Y R Y R | R B R B R B |
| | | |
| R B R B R B | B G B G B G | G Y G Y G Y |
| G Y G Y G Y | Y R Y R Y R | R B R B R B |
| | | |
| R B R B R B | B G B G B G | G Y G Y G Y |
| G Y G Y G Y | Y R Y R Y R | R B R B R B |
(g)---------------(y)---------------(r)---------------(b)
| Y R Y R Y R |
| G B G B G B |
| |
| Y R Y R Y R |
| G B G B G B |
| |
| Y R Y R Y R |
| G B G B G B |
(g)---------------(b)
| G B G B G B |
| R Y R Y R Y |
| |
| G B G B G B |
| R Y R Y R Y |
| |
| G B G B G B |
| R Y R Y R Y |
(r)---------------(y)
To understand the importance of the Tartan, there are several points
to consider:
1. By reading off the four colors of a plaid in clockwise order,
starting at an arbitrary point, we obtain four permutations of the
four colors. Quadruples read from different faces are disjoint, so
all 24 permutations of the four colors appear on the Tartan, once
each.
2. Every motion in the group C of whole-cube rotations is a
permutation of the pairs of antipodal corners, and so corresponds to a
recoloring of the Tartan. Some restriction of this sort is necessary
to prevent us from simply drawing a different black-and-white picture
on each facelet and calling that a two-coloring.
3. Point 2 implies that C is isomorphic to a subgroup of S4, the
group of permutations on the four colors. But both C and S4 have
24 elements, so C is isomorphic to S4 itself (a fact well-known to
crystallographers).
4. Since every color permutation is realizable by a whole-cube move,
there is only one Tartan (up to whole-cube moves). This is why we use
colors as labels, rather than some FLUBRDoid positional scheme. [The
actual choice of colors and the name ``Tartan'' arise from the DoD
Ironman project.]
5. Every reflection of the Tartan is color-equivalent to a rotation.
In particular, the identity is color-equivalent to a reflection
through the center of the cube. If you were to lend your Tartan to
someone who ran it through a looking-glass, you could not discover the
fact except by removing the face-center caps and examining the screw
threads!
We have constructed a Tartan from a Rubik's cube and colored tape.
Due to the similar appearance of the plaids, it takes us several times
as long to solve the Tartan as it takes to solve Rubik's cube.
Our search for pretty patterns has not been particularly rewarding.
Part of the reason seems to be that the cube's appearance is strongly
constrained by the Tartan's coloring. On Rubik's cube one may make a
particular face pattern (e.g. orange T on white background) using any
of several identically colored facelets. On the Tartan, however, the
plaid on any facelet of a cubie, together with the orientation of the
plaid relative to the cubie, determines the plaid and orientation of
the other facelet(s) of the cubie.
The one nice pattern we have is in fact the conceptual precursor
to the Tartan. It is Pons Asinorum (FFBBUUDDLLRR) applied to the
position shown in the diagram above. In this position, the plaids
of adjacent facelets line up with each other to display the same
arrangement of plaids, magnified by a factor of two. Each face looks
like the following, for some assignment of colors to the numbers 1
through 4:
(1)---------------(2)
| 1 2 2 1 1 2 |
| 4 3 3 4 4 3 |
| |
| 4 3 3 4 4 3 |
| 1 2 2 1 1 2 |
| |
| 1 2 2 1 1 2 |
| 4 3 3 4 4 3 |
(4)---------------(3)
---
Date: Thu, 26 Aug 93 10:30:57 -0400 (EDT)
From: Dan Hoey <ho...@aic.nrl.navy.mil>
To: Cube Lovers
Subject: Tartan reborn (Re: Tools lost in the mists of time...)
Alan Bawden mentioned the joy of rediscovering his lost cube-solving
techniques. This happened to me about three years ago for an unusual
reason. I've become active in science fiction fandom, and fans
determine where the World Science Fiction Convention (Worldcon) is
held each year by running miniature political campaigns. A friend
of mine was bidding for Glasgow, and she asked if I had any `plaid
things'. I told her I had a plaid Rubik's cube, and a political
strategy was born. The plaid cube is of course the Tartan, which Jim
Saxe and I discovered and described in this group on 16 February 1981
(see archives). I blanked some old cubes, and figured out how to use
spray paint to efficiently create Tartan cubes. I produced a half
dozen or so, and they make good conversation pieces at conventions.
Unfortunately, I seem to be the only convention-going science fiction
fan who can *solve* a Tartan (with the possible exception of Phil
Servita <mei...@gaak.lcs.mit.edu> who as I recall figured out an
effective method but wearied in its execution). So I would see a
scrambled Tartan at a convention party, and fix it, and put it down,
and five minutes later it would be scrambled again. I quickly found
out how rusty I was, and through the enforced practice I've gotten
about as good as I was a decade ago. But some of the Glasgow
promoters took Tartan cubes over to the UK, and those cubes just never
get solved. I sent them instructions for solving it, but I don't know
if any of them have figured out the instructions.
Well, eventually they told me they really wanted something mere
mortals could deal with, and I painted some pieces of wood plaid that
they could use for doorstops. I was surprised, though, to find that
to make a plaid pattern going around a corner, if you only have four
colors of paint, it seems the *only* thing you can do is use a
coloring locally identical to the Tartan.
As for the cubes in the UK, I expect to get there in 1995. For it
seems the clever ploy worked, and the fans voted to have the 1995
Worldcon in Glasgow. I'm sure they owe it all to the Tartan. Sure.
Dan Hoey
Ho...@AIC.NRL.Navy.Mil
---
[ Dan was listed as an attending member of at least the 1989, 1991-99,
2001, 2003-04, and 2007 Worldcons. I don't know whether he actually
attended all of them. -- Keith ]
Bill
> Anne Hoey wrote:
>
> I am as you may guess dreadfully sorry to report that Dan Hoey is
> dead, and by his own hand. He committed suicide on 31 August.
> The police found him in the bath, dead, with blood all over the
> bathroom. I have been trying to locate people who knew him. His
> two sisters and I are planning a memorial service, also an obituary
> in the Washington Post. So much to do, and such a sad business.
> We will keep you informed.
>
I consider him to be one of my mentors. I admired and respected him more than I can say. I knew he had troubles, but the last I communicated with him he said he felt much better. He seemed happy and more mellow. So I am shocked. Frankly I don't have the words to express how much this saddens me. I owe him a lot. Bill
Keith F. Lynch
> I was horrified to find out last night that Dan had died, after
> doing a Google search for his early work in computational geometry.
It contains over 1700 of his postings and emails. You may enjoy
reading it. If you have any emails or letters from him, I'd be
glad to add them to the site.