Uniform

There's a type of politeness which is to appear roughly as society would expect you to.

I recently made a short journey scooter with a bundle of pool noodles lashed across the handlebars of my scooter. Almost everyone who saw me stopped and stared. Some cars had trouble staying in their lanes because I occupied so much of their attention.

Years ago I did sound engineering and roadying for a show that had a large seated audience. There were a lot of changes during the night so I was frequently on the stage moving equipment, instruments and mics. My mother was amongst the audience and commented the next day that I looked like a member of the public who shouldn't have been there. I bought black work clothes before the next show and wore them thereafter. It made things easier both for me and everybody who wondered who I was.

My sister tells the story of a man who needed more exercise and tried out running. His problem was that he wore ordinary clothes. If your friends, neighbours, or the well meaning public see you running in normal clothes they think you're in a crisis, that you're late to something, or that you're running from something. The only way he could avoid having passing cars stop and offer assistance was to go out and buy running clothes.

Richard "dress for the job you've got" B

Meth

One of the odd jobs I did this weekend was to dye a litre of brake fluid blue.

On a racing car or a track car you change the brake fluid often. The job is either difficult or wasteful because it's pretty much impossible to tell whether you're bleeding out last year's fluid or the fresh stuff you just put in.

You used to be able to buy DOT 4 brake fluid that had been dyed blue to help with exactly this problem. You would alternate colours each year and be confident that you'd flushed out the whole system. However the Department of Transport standard for type 4 brake fluid specifies the colour as "straw", so the blue stuff doesn't comply with the standard and can't be sold as DOT 4. To be fair it would look to the MOT man a lot like you'd accidentally topped up the brake fluid with screen wash.

Some enterprising amateur chemists think that the dye is Methylene Blue. I've bought a gram of it and I'm trying it out. I think I've put about 50mg into a litre of brake fluid. It dissolved easily and it's now a clear and vibrant blue colour. I think a gram of the stuff would be enough to dye a large river.

Richard "That's Probably Why Walter White's Methamphetamine Turned Blue" B

Reliability

I had some difficult car fault finding, driving, and bodging to do this week.

My Fiat Panda wouldn't start, but with jump leads from my sports car it would start. It ran, but it ran badly. I drove it to the shops where it died and wouldn't restart. I walked home and got the sports car and the jump leads and went back to the shops. This time it started but it would only run when my foot was on the throttle. I had an incredibly nerve wracking drive to get it home again without taking my foot off the throttle. I operated the brake with my left foot, I made violent and harsh gear changes at high revs and I had to select neutral in plenty of time before I wanted to stop. I then walked back to the shops, did my shopping and drove home in the sports car.

I convinced myself that the only problem was the battery. I charged it for a few days but it still wouldn't start the car so I took the battery to the battery centre by motorbike, had it tested, and bought a new one.

With the new battery the starter motor would run and the car would sputter into life for a few seconds, but it would die again if you took your foot off the throttle.

During all the jump lead shenanigans I had noticed that the air filter box was  skewiff. Underneath it I found witness marks on the throttle cable adjustment. I messed around with it a little bit and the car is again completely serviceable, although the tickover is now a little high.

My best guess is that the garage slowed down the tickover during the MOT to squeeze it passed the emissions test and it has wandered a little bit since.

Richard "What do One Car Households do in Situations Like This?" B

Scones

Do you like Welsh Cakes? For me it's an almost impossible question to answer. On one hand they're like a flat disappointing fruit scone. And the fruit scone is the second worst scone, behind only the cheese scone.

On the other hand they're an excellent substrate on which to deliver clotted cream.

On the gripping hand, If I'm buying them I'm in South Wales. If I'm in South Wales it's because I'm going to a track day at my favourite circuit. If I'm buying Welsh Cakes, then the Llanelli Co-op is still open. If the Co-op is still open then I got there nice and early. If I got there nice and early, then the M5 and M4 were flowing smoothly.

So I only eat a Welsh Cake on a really excellent day.

So, yeah.

Richard "I Haven't Even Read The Mote in God's Eye" B

Every Day is a School Day

 I've had a couple of funny experiences at the climbing gym. Firstly I split my pants open. I was reaching out wide with my leg and there was the sound and sensation of tearing fabric around my nether regions. I got down from the wall quickly and examined myself. Nothing was on display. It was my underwear which was destroyed, the trousers and my dignity were mostly intact. I'm proud of the achievement, I think it means that my hip flexibility and strength are improving.

Secondly, I was working on a climb at the same time as a group of students and their coach were working on the same climb. One of the students showed me how much further than me she could get. The coach tried to make me feel better by giving me hints, advice and encouragement. For a few minutes I joined the coaching session even though I hadn't booked, I wasn't paying for it, and I wasn't supposed to be part of it. It was the girls under 12 (advanced) group.

Richard "I know my place" B

Conic Section

 Children often ask their maths teacher when they'll use what they're being taught. For me it's so that I can waste a huge proportion of my weekend worrying about concepts that have already been explored centuries ago.

Inside you there are two wolves. One wolf sees interesting maths problems in everyday life. The other wolf likes solving maths problems.

I'm currently down a worse rabbit hole than recognising bad kerning https://xkcd.com/1015/ There are many things that artists get wrong when they paint the moon and I've learned to spot a load of them. I started wondering what shape the terminator (the line between the light side and the dark side) should be and it got a little out of hand.

The moon is a sphere (to all intents and purposes) and the sun is a point source of light (for all intensive porpoises). What shape does the illuminated section have? The limb (the outside edge) is a semicircle. My contention is that the terminator is another arc but I needed to prove it.

Let's say that the outside edge of the moon is described by 𝑥² + 𝑦² = 1

(yes, the coordinate system of my painting is based on the plane of the ecliptic). Let's say that the sun and the painter are looking at the moon from 60° apart so the terminator will be half way between the limb and the centre line. I know that the 1/2 seems arbitrary but if the maths works out I'll go back and replace it with a Greek letter. This will be true all the way up and down the moon because horizontal slices of the moon are all circles, they're all similar, just different sizes. So the question becomes what curve is half way between 𝑥² + 𝑦² = 1 and the vertical line 𝑥 = 0 ?

𝑥₁ = 𝑥⁄2
𝑥 = 2𝑥₁
𝑥² + 𝑦² = 1
(2𝑥₁)² + 𝑦² = 1
4𝑥₁² + 𝑦² = 1

Does that look like it describes a circle? No it doesn't, that's something to do with an ellipse. An ellipse! Hardly are those words out when an image out of maths books troubles my sight. If the moon is a peeled orange (you don't get poetic metaphor like that from amateurs like Yeats and Tennyson) the terminator is the shape of one of the segment lines and they're circles around the orange but angled towards us somewhat.That's the same as saying it's the shape made by cutting a cylinder at an angle and that's the same as saying it's the shape made by cutting a cone at an angle and that's the same as saying it's an ellipse.

So to do the terminator on a moon in your painting you'd seem to need to trace round an ice-cream cone that's been cut off at an angle. Or a traffic cone for larger works.

Richard "There's a Bad Moon on the Rise" B