Message #2231

From: Roice Nelson <>
Subject: Re: [MC4D] "Three strange {8,4} colorings"
Date: Sat, 02 Jun 2012 09:58:53 -0500

Melinda asked if I could add FEV versions for the {8,4} puzzles, so they
are available now<>

For the other FEV puzzles we’ve discussed, I set the E and V cut diameters
to the tiling edge length, then made the F cuts tangent to the V cuts. On
the {8,4} tilings, you get some tiny pieces with this approach, so I made
the {8,4} FEV puzzles slightly different. The V cut is still equal to the
tile edge length and the F cut is still tangent to it (on this tiling, they
turn out to have the same radius), but I configured the E cut slightly
smaller. It is set to intersect where the F and V cuts are tangent. I
like the result<>.
49 stickers per face.


On Fri, Jun 1, 2012 at 10:22 AM, Roice Nelson <> wrote:

> I can’t help in the solution department, but here is some basic info about
> the topologies :)
> *{8,4} 5-Color*
> Faces 5
> Edges 8
> Vertices 4
> Euler Characteristic 1
> *{8,4} 9-Color*
> Faces 9
> Edges 16
> Vertices 8
> Euler Characteristic 1
> *{8,4} 10-Color*
> Faces 10
> Edges 16
> Vertices 8
> Euler Characteristic 2
> So the first two have the topology of the projective plane
> (non-orientable), and the last of the sphere.
> Anyone want to figure out counts and kinds (henagons, digons, etc.) of the
> particular faces? The 10C should have a nice, planar graph representation.
> Roice
> On Fri, Jun 1, 2012 at 5:23 AM, Melinda Green <>wrote:
>> That was about all that Roice said about these three puzzles and nobody
>> seems to have noticed them. That’s understandable because he was
>> dropping hundreds of new puzzles on us at the same time and the {8,4}s
>> were at the very end. Well I stumbled into them a couple of days ago and
>> can say "Mighty strange indeed!" As you know, I’ve been focusing on
>> edge-turning puzzles that I can solve intuitively and found the 5-color
>> and 10-color versions to be a lot of fun. They start out easy enough and
>> finish with enough of a brain stretch to be quite rewarding to solve. I
>> had tried and failed with with the 9-color version after a couple of
>> half-hearted attempts, but since I had solved the other two I figured it
>> was time to make a serious attempt to collect all three, and all I can
>> say is "OH………………………….., MY GOD!" Roice mentioned
>> that they have some interesting topological properties that would be fun
>> to study and I completely agree. The best single word I can find to
>> describe tthe 9-color version is "perverse". Rather than try to
>> describe what I found, I want to invite Ed and Nan and any other serious
>> puzzlers to give these a shot. Then please let us know what you think.
>> Do they yield easily to your standard methods? Do the face and vertex
>> turning version behave as oddly as the edge-turning? I definitely want
>> to learn more about these bad boys!
>> -Melinda