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Tue, 11 May 2004

International Science Fair

David Feinstein, applied mathematician and former TA for Feynman at Cal-Tech, delivered his presentation about truth and certainty this afternoon (yesterday afternoon by now). I was one of the group leaders (shop talkers) at a table for high school aged competitors from all over the world (Cleveland, Alaska, Malaysia etc. at my table).

Later, I looked around at the exhibits (still being set up -- open to the public starting Thursday). This contraption solves a Rubic's Cube -- a computer driven device.

rubicsdevice

At dinner later, in the huge Convention Center ballroom, I met a patent attorney from Munich -- this was his first visit ever to the US, though he'd traveled in Asia and South America. I invited him out for beers (we took public transit over to my neighborhood) then drove him back to his hotel. We had a fun time comparing notes.

swen

[00:00] | [wanderers] | # |

Russell's Packing

supplies1

OK, so for some weeks now Russ has been sending me excerpts from this dialog he's been having with Tim Cox. Last time he called, I was riding a 30 mile loop, training for the STP, and by the time our chat turned to synergetics, the trucks were whizzing by at close range, and I couldn't concentrate.

So tonight (that would be Monday night -- blog entries after midnight, so Tuesday) I decided to get to the bottom of what he's been talking about and called him to request a simple explanation -- which I got, and summarize as a project (which I undertook soon after our conversation).

First, I went to Freddie's (local supermarket) and bought these supplies: marbles (pack of 0.75 for $2.99), superglue that works with glass, some clay to hold the marbles in place.

supplies2

Next, I glued marbles into tetrahedral clusters. What Russ has been telling me is you can build the CCP (= IVM = FCC) just with these clusters, and no other assembly. It's like they're space-fillers, although we're not talking about solids here, but agglomerations of spheres that complete the IVM. We've been overlooking this simple solution: just build it will all-regular-tetrahedral clusters.

OK, so here you see the clusters.

clusters

Then I make a base as per Russ's instructions, and fill it with an inverted tet (pointing down).

base

fillbase

I started with lighter and darker colored clusters, so I could distinguish up from down, but the marbles really weren't balanced that way in the baggies I got, so the coloring scheme broke down towards the end.

Another tetrahedral cluster on top completes the 3-frequency tet.

3freq

It didn't take long to expand out to 4-frequency.

4freqa

4freqb

Thank you Russ, I understand now what you were saying.

[00:00] | [synergetics] | # |