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Since I was alone through the holidays I decided to run an experiment. I set all my task priorities to zero for the last few days, leveling the playing field. The result was pretty awesome. I did two days of just see a task and do it, not worrying about if there was anything-higher priority to be done.

What interested me is that I had blinders to a large number of tasks that I eventually intended to get around to, but which were perpetually starved by higher priority tasks. A good example is this tool rack. I had been meaning to build one for a while.

The rack lets me easily carry wire cutters and a few spools of wire around the electronics shop. It took less than an hour to make, and I liked it so much I made four more. I also made significant headway on 3 projects I care about too much to let die, but that always seem to be eclipsed by higher priority projects.

Would I do the whole “see a task, do a task” full time? Heck no. I do think this is going to be my new holiday tradition. The results were more promising than experiments with non-traditional sleep schedules, without feeling like you were hit in the head with a rock if you fell off the sleep regime.

So a while back I tried and online dating site. As part of the process they ask you a bunch of questions. One of which was – “on a typical Saturday night you are…” with a bunch of options. None of which seemed a good fit. So last Saturday night I was looking at the bench next to my mill where I was working and it struck me – yeah this is a pretty good pictographic representation of my typical Saturday night.

When my dad retired he gave me a few tool boxes that had belonged to my grandfather. I ended up turning one of the new boxes into my “tap and die” box. For years you only ventured to open it at the peril of loosing ten minutes looking for the tap or die you were really after. A task that was typically 1-2 minutes of looking and another 8-9 minutes trying to jam everything back in the box.

I finally had enough after a spectacularly time consuming hunt for a tap lead me to buy one I already had but could not find. I mean it is a 2.5 square foot space! So I went and divided the tool box into tills. Here are the results.

When you open the tool box you have direct access to your basic smaller taps, guide blocks, a tooth brush, flash light and tapping compound.  There are normally a set of gloves in here as well. I made the top till extra deep so I could still throw a few small odds and ends in there if needed.

The entire top tray lifts out to reveal a inner tray – which contains two smaller tills. So that gives me 4 compartmented areas to store things. The top ones I use for taps, and the lower ones for dies. You can see the box pictured here with all the tills and trays out

Being a big fan of duct Jason has twelve brand new rolls out in the garage, but unfortunately none of them say how much tape is on a roll! To help Jason plan out a big duct tape project can you figure out how much tape is contained on each roll? You are able to measure that the tape is wrapped around a cardboard tube with an outer diameter of two inches, and that the tape wraps around the tube until it has an outer diameter of 3.5 inches. The tape measures out to be 0.01 inches thick. What length of tape is contained on each roll?

The wording needs a bit of work – specifically I want to add some reason why Jason wants to know how much tape is on each roll – but for now I am stumped. I originally wrote it with him wanting to make a suit out of duct tape for his high school reunion – but the absurdity eclipsed the problem. Eclipsing the problem is sort of an ongoing problem when I write this stuff up.

My main problem here, I think, is that it is a very simple problem if you have the tools to solve it – but I am not sure if it is too difficult if people have never worked with power series. I wrote up the solution as an introduction to them – and that is the goal of this problem: to get people thinking with power series.

As always my answer is on the book site I set up. The comments below are just for discussing the problem / people to post their answers.

[Update: This is why you dont write down things in the middle of the night… the sum I wrote up and *did not notice* is totally wrong. I also made an error on another problem I wrote down. Anyway, the error here is that the sum from 1 to N-1 does match with [((N-1)+1) + ((N-2)+2) + …] becomming N^2/2 not N/2. I just forgot to write down N^2, got distracted, then came back and finished it off that way. Crazy. Yet again I need to never do math after midnight. Anyway ignore what I wrote up below – essentially you have the same solution but the sum you compare with is N^2/2 for a list from 1…N-1 in value. Not going to delete the post as this makes a good example of a simple mistake that can even seem resonable if you dont doubble check your finial result! So might stick this in the book as an example of what NOT to do. ;-) ]

So when preparing for my Amazon interview I brushed back up on computer science as opposed to nocking the rust off my coding skills (read getting back to where I could code my way out of a paper bag). Anyway one of the things I ran across when prepping for the interview was a numeric sum problem. Basically you are given a list of numbers ranging in value from 1 to N, in unsorted order. One of the numbers is either missing or duplicated – write a number to find the function.

One solution is to sort the list and then search it for the missing / repeated value. Should be able to do this in O(nlogn) time. I need to check but I *think* a radix sort would work here for N time. A much better solution is to remember the series equivalent of 1…N. Then you can sum the numbers you were given, compare that number with the series equivalent, and just know the answer. Since it takes only one pass over the list it works in O(N) time too.

So I had to wait until daytime to take some better pictures of my lathe. Unfortunately I was using my iPhone, which means I got like 2 pictures that were OK for the 10 I tried to take. I really need to buy a real camera.  And just to be clear I was not using the hammer to adjust anything on my lathe!

The integrated gearbox quick-change gearbox means I can cut threads on this lathe – which I am fairly excited to try. Yeah, I need to get out more. I am thinking the stand will also give me a nice place for mounting the DRO hardware (a digital readout that tells me where the cutting tool is currently positioned).

Well, today I went and got a “New” lathe. Actually, as close I can figure it is from the late 60s – but that still makes it about 20 – 30 years younger than my other lathe. It is a Craftsman 12”x36” – like these.

I was already looking to add a quick change gearbox to my older Atlas lathe, and build a stand for it. So when I saw this one come up on craigslist I figured I would break even over upgrading my old lathe if I can sell the old one for a decent price.

Looks like I will need to make a new motor pulley, and replace the headstock bearings soonish – but I am kind of excited.

Here you can see the lathe wrestled into the corner of the shop. Joel came over and bailed my ass out big time. It was clear I would have dropped the lathe and maybe screwed up my truck the way I was planning on moving it if none of my friends could come over.

Implement insert for a binary tree

Implement an algorithm to insert in a sorted list.