## Friday, January 22, 2010

### Roman numerals

Watching a film last night with someone, and we watched it through to the end as it was one of these that has a little bit after the credits. So post-film she mentions something about the special effects and I reply that this film was after all made in 1985.

"How do you know that?"
"It was on the credits MCMLXXXV"
"You can read them that quickly"
"Yeah have been able to since as long as I can remember"
"Yeah well that's just you isn't it"

Thanks; I think :-) I'd never really thought about until then, but it's like being able to read reverse writing or when it's upside-down just catches me by surprise that this isn't something everyone can do with ease.

So anyone got something they can do that they're surprised other people can't?

Orphi said...

I can program in Haskell. It seems really quite trivial to me, but everybody else seems to think it's insanely hard…

FlipC said...

Yeah but Haskell is insanely hard :-P

I mean I find programming hard. I can do it, I can follow the logic and understand it, it's just not something that gels inside my head it takes effort and concentration to do things 'proper' programmers just do.

Ah an analogy - I can fold my arms up into the prayer position behind my back. there's a small amount of strain at first, but once in place it's quite easy to maintain; that's how I feel about programming.

Orphi said...

sum [] = 0
sum (x:xs) = x + sum xs

The sum of nothing is zero. The sum of something is the first thing plus the sum of the other things.

Seems pretty trivial to me. ;-) But then, I'm a maths nerd.

Alternatively,

fibs = 1 : 1 : zipWith (+) fibs (tail fibs)

computes all the Fibonacci numbers on the universe, and takes about a page and a half to explain. YMMV.

I can also count in binary, do binary arithmetic (given pencil and paper, obviously), and convert expressions into Polish reversed lists mentally.

I can also do algebra. Apparently most people can't.

But no, I can't read unside down. At least, not fast quickly.

FlipC said...

"takes about a page and a half to explain" do I sense another entry from yourself :-)

"I can also count in binary" Oo I mean I know how to calculate in binary but I can't look at 10110 and say that's 22 without a significant pause.

"I can pat my head while rubbing my tummy." Yeah why exactly is that deemed difficult? It's like being able to hold your palm out fingers side-by-side and then move them in batches - an extended live long and prosper thing.

Orphi said...

Heh. It's a list of numbers, recursively defined in terms of itself. This would of course be completely impossible if it weren't for the fact that, like Mr Heisenburg's undead cat, the list elements don't “exist” until you “observe” them.

But to really explain it, I'd need to draw a diagram. (Or six.)

I can count forwards and backwards in binary, but I can't do base conversions of any sort mentally, no. I recognise a few low numbers instantly (e.g., 400 hex = 1024 decimal. 11 binary = 3 decimal. 1010 binary = 10 decimal. etc.)

I have no idea why the thing with the rubbing is considered difficult. Seems easy to me. Then again, I play keyboard instruments, particularly Bach fugues, which regularly require both hands (and possibly your damned feet!) to be doing untirely unrelated things simultaneously. This seems far more difficult. :-P

Oh, and my mother thinks I'm some kind of genius because I can move my eyebrows independently. Watching her trying to do it is quite comical…

FlipC said...

SchrÃ¶dinger, Heisenberg what's the difference if they're both unobserved ;-)

You can move your eyebrows independently! By the gods the man's a genius. I can't do that. Oo I can wink with either eye though how's that?

Anonymous said...

Hi, I am totally going off the subject here but I'm at my wits end! Does your amazing Roman numerial chum know what 30th April 2010 is in Roman numerals? I am getting the date of my upcoming wedding engraved for my husband... just to show willing, I got as far as XXX.IV.MMX... please help... I am blonde and have been let down by the British education system...I suspect my spelling and grammar already gives that away! Thanks for any help!

FlipC said...

Well XXX is 30, IV is 4 (new style, old style it's IIII) and MMX is 2010.

So in the UK system XXX.IV.MMX would read 30.4.2010 and with that 30 and full 2010 you wouldn't be able to confuse it with any other system.

So if that's what you're after then you've got it right. If you're mad (which I doubt) and want the date as per the real Roman system then it'd be Pridie Kalendis Maius MMDCCLXIII a.u.c. or the day before the first day of May 2763 from the year in which the City was founded - yeah I'm doubting that's what you want :-)

Congrats by the way hope you have a great wedding.

Dan H said...

Yeah, I can do the belly/head thing to, and I also play instruments that require different actions of all your limbs, while counting bars in my head. Yes, I'm a drummer. I can read upside-down and, with a little more effort, sideways.

I've always been surprised when people are surprised at me knowing useful things or being able to learn things quickly. I concur that you don't really notice that you can do things, you only notice when other people can't.

FlipC said...

Yet I can't play a keyboard, that level of dexterity eludes me.

Brain-flash sort of off-topic but try this - Hold up your dominant hand and draw a square in the air, now do it with the other hand. Did you start with a corner? Did you start with the same corner or a mirror-image?

Now use both hands to draw one square. Did you start at a corner or the middle of a side?

Now with both hands draw a square with each at the same time. Did you start at the same point or perform a mirror operation? Now try doing it the opposite way.

Orphi said...

People tell me I'm a really talented musician, but I have another theory:

When given a new piece of music, it usually takes me a ridiculously long time to learn to play it. It's like my fingers are dyslexit and won't operate in the correct sequence without days and days of practising.

So I don't think I'm naturally talented. Rather, I think I'm too stupid to get bored and go try something else (e.g., having sex with girls). Instead, my stupid little slow-brain sits there for days and days trying to solve this pesky little puzzle, until eventually I manage to do it by sheer persistence rather than by actually possessing skill.

Try this as an experiment: Find an activity, do it every day of your life for 20 years solid, and then tell me if you get moderately good at it. ;-)

FlipC said...

You do yourself a disservice, I think you can only get so far through sheer repetition and muscle memory.

You can get better by practising, but I think you can tell if it's purely by rote rather than having some spark of talent there.

Don B said...

I'm busy for 4 days and the blogs and comments go mad.

You end this blog "So anyone got something they can do that they're surprised other people can't?"

Old skills that I can still calculate - money in old LSD (ie in old currency)
- distance in miles, furlongs, chains, yards and inches. (We still use miles and chains every week on the railway)
- library Brown charging systems, Brown classification system and I can remember pretty well the entire modern public library Dewi classification system to 6 places after the decimal point.
- give accurate Ordinance Survey reference data

FlipC said...

Ha if you want mad go see the letter in the Shuttle 91 comments and counting.

I was raised with decimal coinage so never had to calculate in 12's and 20's for that. I was, however, educated in metric measurements, but taught in Imperial which left me as a child with an inability to state distances. It was only later dealing with lengths of timber that I could start to tie the two together.

The cataloguing talent is impressive, but what do you mean by accurate Ordnance Survey reference data?

Dan H said...

I was reminded of another last night. In a pub, I'll hear the muffled bass-line of a piece of music, and quickly identify it. Other people around me will be completely puzzled, listen to it for another 16 bars, and say, "Oh, is it?"

The obvious explanation is that as a drummer, that's the part of the music I notice most, but that doesn't account for why I can go on to tell you, "and this isn't the recording that was on last week," and people are surprised at that too.

I seem to be completely the opposite to Orphi. My skill at sight-reading is vastly ahead of how much I improve with practice. To turn your question around: find an activity, don't do it for 20 years, and then tell me if you get moderately good at it. There's no other way to become an expert, or renowned, with a particular skill or field of knowledge, than years of practice.