Sudoku Musing

A SUDOKU MUSING

One of the things I'm a little bit proud of in my journey of sorting out how to solve Sudoku puzzles is that I've never looked for any advice. Early on I wrote some VBA code to quickly get past the easy 'giveaway' answers, which was fun in itself, but since then I've only relied on methods and rules I've come up with or set for myself. Neither am I a master of it by any stretch of the imagination, I make a lot of stupid mistakes and keep getting the feeling that I'm missing something in my logical analysis, hoping that another revelation or strategy will appear.

To start with I like the simple approach, it's either this or it's that, binary if you will. However I've not yet got a foolproof notation of such which I think leads to misinterpreting my notes. After the Excel VBA phase I decided that too many notes were not helping me, a cluttered grid gets in the way. In a row, column or square of 9 I'll note two possible places for a number (which I'm thinking sometimes gets me into trouble). More reliable, I think, is determining that a given cell can only be one of two numbers, so I'll note that too. I don't want the clutter of more than two possibilities happening for a given cell, although that still happens sometimes with my current approach.

But that's not what I wanted to talk about here. There's a pattern I've seen but have not yet drawn any conclusions from, so I thought I'd walk through where I am at the moment then see how this particular example plays out in hopes of learning something. So let us start with the 5-star puzzle ("by Dave Green") presented in the Akron Beacon Journal, Sunday October 3, 2021.

In order to discuss this, I'll need a way of identifying cells.  I'm sure folks have come up with their own ways of talking about this but as with all other things Sudoku thus far, I'm doggedly blazing my own way. The first and perhaps simplest approach that came to mind was simply to ID each cell by row and column, AA through II.  This pays no regard to squares of 9. That would work but...

I like this second approach that came to me. Each square-of-9 (call it a GROUP) will be identified with a letter A through I. Each cell within a group will be identified in the same way with a second letter. Rightly or wrongly I thought that might steer us/me through the grid faster. As with the first ID approach, the very top left cell would be AA, but now the fourth cell in the top row becomes BA. 

Thus, in the puzzle presented below (Oct. 3 five-star): cell AB=9; CA=2; CC=4 and so on. (Note to self: in Paint.net the bigger numbers are calibri 20 bold, notes are 10 not bold.)

I started solving the easy bits as follows with my entries in green & notes in red:

This is where it gets interesting with the eights. In group C there are a solid pair, solid in that within both that group and entire row it's one cell or the other has to be an eight. Proving or disproving either one will have immediate result. The same can be said of the eights in group H. 

Less solid are the two eights in the last row, they're a valid pair in that the logic is good for that entire row, but because they're in different groups I might be deceived. The problem is that within group I the two potential eights I've identified so far aren't the only candidates. Cell IA might be an eight, I don't know yet. If IA was shown not to have "eight potential" that would lock the other eights in. Proving any one of them would toggle all the rest of those eights on or off.

I'll watch what happens, but even if IA turns out not to be an eight I won't really know if this is a pattern I can 'take to the bank', it might just be in this instance.

A little later, not getting very far but here's another yellow-liner that makes me wonder if it's safe to assume these are my good choices for fives. There are no super-solid pairs as the semi-solid pairs (dashed lines) are in rows or columns but not within groups. The dotted lines connect questionable pairs, each groups involved has another possible five that I've not noted.

If this pans out, be sure to notify Oslo.

Summary: If I can trust these associations and infer that the questionable cells don't contain those fives and eights then maybe I can move ahead. Otherwise I'm a bit stuck at the moment. 

Below see the questionable cells: orange for cells I'm going to presume are NOT five; purple for the cell I'll presume is NOT an eight (IA).

Two days later I'm still stuck, BUT I think I proved that putting a five in any of those orange cells would result in problems for the fives. Not so much luck with the eights. Neither could I get anywhere along those lines with the sixes. 

Maybe it's time to erase the whole thing and start over, perhaps I made a mistake somewhere. Doh!

Sax Strap

The traditional saxophone strap can be annoying. 

I looked into the fancy harness things that are available but before getting very far came a little improvisation with what I have on hand. 

Lo and behold my first try ain't half bad. I don't know if this is some kind of luggage strap or what, but all I had to do was bend that hook from a bit of sturdy wire (I think it may have been a fly-swatter handle).

Tie Dye by Ilene Weisberg

Do not attempt to adjust the controls of your television set. 

I added this goofy pixelated picture just because I always liked this effect.

Update: This isn't the end-all. Today I'm using a combination of what's shown with the trad neck strap.

A me-looking-down view. 

The Buescher

To get a concert C I have to finger a Bb on this horn (should be A). 

That puzzles me, as since I've owned it I thought it was an alto, presumed to be an Eb instrument. Note: I'm not a sax player, haven't touched this in decades.

MYSTERY SOLVED: I wasn't pushing the mouthpiece on far enough! 

But maybe my mouthpiece's opening is too small, going to try a new one. Sid the repair man was certainly able to get his to the right place.

Case measures 10-3/4" x 24-1/2".

This part of the horn measures 21-1/2".

Online lookup tells me this is a 1923 horn.

Phone Holder Project

Problem: phone holder won't expand to hold 6.125" length phone.

Challenge: design a solution which is reversible (avoid drilling holes, cutting etc); don't remove existing capability (example, extending the top bracket - my first thought - may solve the initial problem but remove the ability to hold a smaller phone or horizontally positioned phone).

My second idea was something like this. Even though the screw could have been replaced with a tie-wrap (zip-tie) I felt it needed a more rigid piece of metal than I had handy or could mock-up quickly.

My third idea was to suspend this piece from the existing lower supports. It is cut from some scrap sheet metal. The plastic edging prevents scuffing the existing supports. I hope the following pictures are self-explanatory. 

Submitted for evaluation, I need to know if this works. 

Two possible complications come to mind: phone angle may now be somehow unsatisfactory; position in vehicle with phone lower may inhibit connection of power/data connector.

If I'd had a larger piece of scrap on hand I might have extended it so it could have been tied in place to hold it more rigid when phone is removed. Prototype could easily be added to in this way.

2021-06-06_PatioParty

I wish I'd got the camera out before Laura Nick and Cindy left.

Richie and Gareth

Left to right: Richie; Christine; Pete; Alan; Gareth; Nancy; Emmett.

PET Diffuser Project

 April 2021

This is a very bright spotlight, too bright sometimes.

A diffuser I added to mellow it out. However, more mellowing was needed.

Picture if you will the very 3D shape of what I cut from this old PET bottle.

Since I wanted a flat disk I put it in the oven (cookie sheet with parchment paper) at maybe 250F. That softened it up and maybe would have been good enough. I wasn't sure so I bumped it up to 300 or maybe 350 which turned out to be a bit too much, the edges started to melt. 

Then I attempted to squash it flat between two cookie sheets and got what you see below.

Haven't tried the brightness test yet.

Damaged Lens

March 20, 2021

I think this Canon EF 70-200mm f/2.8L USM  remains the most expensive lens I have ever purchased. Sadly (OK, heartbreakingly) it fell off the tripod a couple of years ago.

As you can see the glass is intact but manual focus and zoom are now very tight. They can move but not without a great deal of effort. Meanwhile, autofocus appears to be unaffected. I snapped the below shots with Canon T6s in JPG "L" mode. They are unmodified except by scale and/or cropping. 

Note: this lens can work with the Canon 1.4 extender (see below).

Approx 9.5 feet, cropped and scaled 50%.

IMG_6912 1/640 sec. f/5 190mm ISO 100

Approx 43 feet, cropped and scaled 80%.

IMG_6920 1/320 sec. f/7.1 190mm ISO 100

Approx 9.5 feet, cropped and scaled 50%.

IMG_6921 1/320 sec. f/6.3 190mm ISO 100

Approx 9.5 feet, cropped and scaled 50%.

IMG_6924 1/320 sec. f/6.3 190mm ISO 100

Approx 30 feet, cropped and scaled 80%.

IMG_6934 1/320 sec. f/7.1 190mm ISO 100