Teacher FAIL failing fails.

A little discussion about the teacher fail that is issued at failblog.org.

The question

The post shows this math question:

It took Marie 10 minutes to saw a board into 2 pieces. If she works just as fast, how long will it take her to saw another board into 3 pieces?

The student answer is "20 minutes".

Rule of three

The answer is considered to be wrong by the teacher, who corrects it using the rule of thee:
1 piece = 5 minutes,
2 pieces = 10 minutes,
3 pieces = 15 minutes
and thus, according to the teacher, in 20 minutes Marie will have 4 pieces.

Real life experience

Of course, Marie isn’t creating two pieces, one by one, in ten minutes but is rather sawing one cut in ten minutes. To obtain 3 pieces, you need two cuts, thus 2x 10 minutes. Sure it was supposed to be a question about the rule of three. But it wasn’t one.

However. It seems very hard to understand this. I spoke to two people who both had troubles solving this problem. One was thinking about the rule of three and indeed proved the teacher correct… until I pointed out the real work is creating one cut rather than one piece of wood – he picked it up immediately, although he made the remark that this question lacks information and thus can’t be solved easily.

Failing fail

The second person however, still didn’t got it. After a long and bizarre explanation from his side, he came to this conclusion:

  1. You saw the board in 2 pieces and then you saw one of these pieces in two. Here the student is right.
  2. You saw the board in half, then you have two pieces of wood that are half the width of the original. Now, you saw perpendicular to the previous cut. Then, you’ll need to cut through half the width of the original board and thus you need half the time. Thus the total time of 15 minutes

And thus, both student and teacher are right, depending on how you approach the problem.

Failing fail fails

I pointed out that he’s assuming a lot of things. First of all, you need a board that is a perfect square, preferably a cube. Then, you need to saw perfectly in the middle to obtain two equal parts, which can be cut in half the time. But when it isn’t a square, you’re end of story, because you can saw the perpendicular part in less then half the time. Or more, depending on which side you’re sawing.

So that leaves us with another possibility: suppose Marie is just cutting of some corners. Then she’s finished in 2 minutes. Or 3. Or 1.5. Undefined.

And that’s the point my second correspondent tells me … the question lacks information and thus just can’t be solved.

But hey, it’s probably me. I might not be good enough in maths to solve this complex primary school maths problem.

Ever dream this man?


Every night, all over the world, hundreds of people see this
face in their dreams. If this man appears in your dreams
too, or if you have any information that can help us
identify him, please contact us.

thisman.org claims that the project started because the man was first described by the patient of a well known psychiatrist and later recognized by several patients of different psychiatrists and they want to find out who he is.

Some state they fell in love with him. To some he gave ’em advice. I think he’s just creepy.

A well-known psychiatrist. Where did I read this before?

Sure this is another hoax, sure this is fake, however, clever found. How to know for sure? Two things.

So be prepared and remember not to forward this when it appears in your mailbox, or this man might start chasing you in your dreams…

Natuurlijk niet

Natuurlijk niet

Natuurlijk zit ik niet in Nieuw Zeeland. Als ik daar al ooit in mijn leven geraak, dan zal het niet voor in de zeer nabije toekomst zijn. Heel erg jammer. Gewoon thuis en op het werk zoals de meeste mensen, daar zit ik. En ik dacht dat dat wel duidelijk zou zijn door een slecht getrukeerde foto van een sjaal en winterjas op een exotisch strand bij de post te zetten…

Zondag hoorde ik op de radio vertellen dat Britse verzekeringsmaatschappijen aan het overwegen zijn om hogere premies door te rekenen aan mensen die actief zijn op sociale netwerksites zoals Facebook en Netlog. Reden? Sommige mensen zetten heel hun leven online, zodat inbrekers gewoon kunnen gaan Internet Shoppen om te zien wie wanneer afwezig is.

Mijn bedenkingen:

  1. Facebook en Netlog zijn niet als enige gevaarlijk. Wanneer je vragen post op vakantieforums in de stijl “Hey, wij vertrekken vrijdag voor drie weken naar Nieuw Zeeland en we zouden graag wat interessante trekpleisters en gezellige restaurants willen weten…” dan ben je ook verkeerd bezig en dan ben je niet eens actief op facebook
  2. De lijn moet dan doorgetrokken worden. Vrienden, buren, familie, collega’s weten evengoed wanneer je hoelang naar waar op reis bent. Je hebt geen controle over wat zij allemaal over jou online zetten. Zij moeten zelfs niet actief zijn op facebook om het aan de verkeerde mensen te kunnen doorvertellen: “Neen, ik kan nu niet komen want ik moet de brievenbus gaan leegmaken bij … want die zit voor drie weken in Nieuw Zeeland… Ja, echt he! Volgens mij is het daar ook schoon! … Ja, ik weet ook niet waar die dat geld vandaan halen…”
  3. Ik heb werk! Alleen, ik heb niet het geluk om thuis te kunnen werken. Misschien moet mijn verzekeringspremie dan ook omhoog, want inbrekers kunnen daar ook meteen achter komen, zonder dat ik het op facebook zet.
  4. Sarcasme alom: als ik naar de winkel ga, blijft het huis soms onbewaakt achter. Krijg ik dan de keuze om ofwel mijn verzekeringspremie naar omhoog te zien gaan ofwel te verhongeren?

En hoewel we in België nog niet zo ver zijn, ook hier is het facebook-fenomeen opgevallen bij de verzekeringsmaatschappijen. Ze wachten echter eerst het onderzoek af. Gelukkig hebben ze nog twijfels bij dat principe. Zo’n uitmelkers zijn het voorlopig dus niet.

Pittig detail: de websites van ING en Dexia zijn net dat weekend gehackt geweest…

Wees gerust. Ik ben voorlopig echt niet zo stom om te vertellen dat ik niet thuis ben, op een moment dat er niemand thuis is. Dus wanneer ik op het Internet smijt dat ik in Nieuw Zeeland zit, dan mag je er gerust van uitgaan dat dat absoluut niet zo is… Helaas, want volgens mij is het daar echt schoon…

PS: Dit is voorlopig de laatste keer dat ik een walgelijk gewone webcam foto online zet. Beloofd.


WP-SpamFree Today, I upgraded WordPress to version 2.8.3. I upgrade immediately when a new version is available. And these days, I don’t even test this. I really like WordPress as it is one of the most decent, new-technology, web 2.0 driven, extensible blog I’ve ever seen. The upgrade goes automatically. And it works like a charm.

Well, almost.

People started to complain that they couldn’t post any comments to my blog anymore. They got the notice of SpamBam that spam comments were not allowed and JavaScript should be enabled. But users are definitely NOT spambots and JavaScript was enabled, so I started a search.

SpamBam uses a random key to determine whether the posted key was the same as the previously generated one. This key was regenerated after posting the comment. I assume that WordPress now calls the do_action(‘comment_form’… not only when generating the page, but while posting the comment as well. And there’s the problem. SpamBam registers the generation of the key in the comment_form action, so the key is regenerated so that it doesn’t match the key on the blog page anymore.

Since I didn’t immediately find a solution for this and since SpamBam isn’t updated since ages, I started to search for another anti-spam plugin that doesn’t work with captcha‘s (extremely annoying and not working after all) and is really reliable… I found WP-SpamFree which seems to use about the same technology as SpamBam, but a little more sophisticated and it was updated only recently. It feels more solid and commenting now works again.

I now enabled a logging feature to see how many spam comments are blocked, just to see whether it is actually working. And ehm… hopefully I don’t end up in receiving spam comments again. But I doubt it. Since its installation, WP-SpamFree blocked 11,827 spam comments already.

Autofill in Mail.app

When you don’t really know how to call something, it’s hard to find it. I tried “mail.app saved e-mail addresses” or “mail.app autosave e-mail address” and still Google gave not the required article. At least I thought.

An annoying thing about Mail is that it saves e-mail addresses to which you previously sent some mail to. It isn’t necessarily annoying, but it is when you can’t change the format. Jack Nickleback might be in your address book, but you might have replied to him while he’s sending with the nickname “Jacky Nickly 98347 <jacky @hotmail.com>” and you really don’t want that to appear in your “To:” field. You just want to send it to the format in which you specified his name in your address book. Simple and clean.

Now there is a feature – luckily – to change this, but I expected an option to change those saved passwords. It isn’t. You can go to Window > Previous Recipients and that’s the list of – d’uh – the e-mail addresses to which you have previously sent an e-mail. Bad thing is: it doesn’t show up the name with which they appear in your e-mail message. What you have to do, is remove the names from the list. They will still appear as you type, since they are in your address book and mail searches the Previous Recipients list and then the Address Book.

I found this in an article from someone who does read the manual, so I don’t have to, but it is on the Apple Support Website too.

Open Directory

Blogging colleagues, that’s nice. Follow their private lives or their children growing up, without even visiting them. But what happens when they try to hack their own blog together, using a lot of "cool" technologies which have more a negative than a positive influence on their productivity. We (other colleagues and I) are bashing since forever on planethofstede.be. Of course, we’re happy he finally has some kind of blog in stead of a folder containing a bunch of images, but he is still holding on to the thought that he’s a programmer and he should implement his own blog – a thought I have given up a long time ago. Using pre build software is much easier and is done by people who knows more about these things than you do.

Not only you can’t add any comments on planethofstede.be (and thus we have to use our own blogs to comment) and is the name that shows up in Google Reader <div xmlns=”http://www.w3.org/1999/xhtml” xmlns:ns0=”http://www.w3.org/1999/xhtml”>www.planethofstede.be</div> in stead of a human readable name, but even worse is his “photo album” that is nothing but a bunch of public accessible folders in which you have to select every photo one by one and in which you don’t have a clue what the image will look like (no thumbnails, no overview, nothing).

This phenomena has a name. Such a public accessible folder is called an Open Directory and is known on more sites than planethofstede.be. This way, there are people who have written a little javascript that allows you to open the images in such an Open Directory in a more user-friendly way. This javascript however is showing all images in full size and the images on planethofstede.be are not even scaled down, making it impossible to view the entire image at once. So I changed the script in a way that the browser will scale the image down if necessary.

Now, how can we use this script to see planethofstede.be‘s images? Quite simple. Add the script as bookmark.

  1. Copy the following script entirely:
  2. Add a new bookmark (called Favorite in Internet Explorer) and use the script as "Location" or :
    1. If you’re using Firefox:
      • Click "Bookmarks" in the menu and choose "Organize Bookmarks".
      • In the window that appears there, right click on "Bookmarks Toolbar" or "Bookmarks Menu" and choose "New Bookmark".
      • As "Name", you can choose "Open Directory" and you paste the script (you just copied) in the "Location" field.
      • Save that bookmark.
    2. In Internet Explorer, it’s different because you don’t have a procedure to add a bookmark like this, but you can download this URL and copy it to your Favorites folder (On Windows XP, this is the folder C:\Documents and Settings\<username>\Favorites). You can do the same for Firefox: download the url and drag it to the Bookmarks Manager.
  3. Now, go to a folder on the planethofstede.be website – which will show you an index of images – and then Click Bookmarks > Open Directory (i.e. the bookmark you just created). The javascript will be executed and you’ll see the images one above the other.
Admittedly, this procedure isn’t user-friendly at all, but I can’t add a “click here to add the bookmark” since Firefox nor Internet Explorer will allow a creation of such a bookmark. But once installed, you have a nicer way to see planethofstede.be‘s photo gallery.

Edit Thanks Nick (Mr planethofstede.be himself) to add the description functionality to the script. I took my chance to change the script a little more and add some more styling. The script now has a dark background and horizontal lines are separating the images and their descriptions from the next image.

Edit 2: As suggested, the horizontal lines are removed and I’m using a margin of 30px instead. I also noticed the portrait-shaped photo’s still needed scrolling as only the width was adapted, not the height. Now the height is modified if the image is too large to fit in the browser window. I also made the images clickable, so that you can click-to-view the original image. Right click and selecting "show image" would work too, but that implies two clicks and a mouse move – thus more effort 😉

Pin My Picture

Having a colleague who has bought a geotagging device, and one who is thinking about doing the same, is the best way to get interested too. Asking colleagues how they geotag their imagese, is not quite a success, since they can only tell which programs to use on a W*ndows PC. Since I don’t use crap, I have to search a way to do this on a Mac. My Equipment: an HP iPaq 2490, a tomtom bluetooth GPS receiver, Visual GPSce to record my track in NMEA data and a camera from which the clock is in sync with my PDA…

In this post, I am explaining how to record the data, I assume you have your RAW NMEA data file available.


Although the NMEA gps data is a standard, not all programs support that format. GPX is the format which is used by most programs and thus recommended. Now how do you convert your raw data to GPX? There is only one program I know with which you can do this, GPS Babel. This is a command line tool and thus not really user friendly for most users but luckily there are enough GUI’s written on top of this tool.

  1. GPS Visualizer, a website which supports multiple formats
  2. Houdah GPS, a Mac OS X frontend to GPS Babel.

Houdah GPS

I’m using Houdah GPS because I might not be online while I geotag my photo’s and this way, I don’t have to upload my geo data to the Internet. Using Houdah GPS is quite simple:

  1. Select your source Because I have an NMEA file available (recorded on my PDA), I select “File” as source and NMEA as format. I had to rename the extension that VisualGPSce has created: the extension is .txt but HoudahGPS only takes .nmea files but an .nmea file is nothing more than a plain text file, thus renaming the .txt to a .nmea file is sufficient.
  2. Select your data I just leave the default: Both tracks and Waypoints.
  3. Select your Destination data NMEA is the one we already have, so we don’t have to select that as destination. KML can be used in Google Earth, and as I said before: GPX is a standardized file format, so we’re going to create a GPX file. This can be used in google earth as well, by the way.
  4. Convert Now that all the preferences are set, click the Convert button in the left upper corner. A File Selection dialog will appear for a first time. Here, you have to select your .nmea file (remember, it’s just the .txt file that you have renamed). Click "Open". A second File Selection dialog will appear in which you can define the name of your gpx file. Choose a name and click "Save"


With our gpx file ready, we now have to put the geo data in our photos. There are multiple programs available to do this.

  1. houdahGEO, from the makers of houdahGPS. This is share ware and costs $25.
  2. Photo GPS Editor, donnationware.
  3. GPS Photo Linker, freeware and my favourite.

The two last applications doesn’t seem to be maintained anymore, but they do what they have to do, so right now, I don’t pay attention to that.

GPS Photo Linker

GPS Photo Linker
In GPS Photo Linker, click the button "Load Tracks" in the left upper corner and select your GPX file. This may take some time, depending on how many data you have recorded. Next, click "Load Photos" in the upper right corner and select the photos you want to geotag. Not only JPEG is supported, but RAW images are supported as well. When all the images are loaded, go to the Batch tab in the left pane (not Standard or Manual) and click "Batch save to photos". This may take some time too, depending on how many data you have recorded an how many images you have selected.

And that’s basically it. Now your photos are geotagged and Flickr or Picasaweb pin your picture on the earth! But remember: make sure your camera and your recording device have their clocks synced, or else your images won’t be pinned correctly! With GPS Photo Linker, you can shift the time of the photos in order to have them geotagged correctly anyway.

Ze hebben nog gelijk ook…

Natuurlijk wilde ik Hallmark voor zijn en had dus een mailtje gestuurd met vragen over hun FotoFun applicatie en mijn bezorgdheid over het feit dat het ding maar 3MB had doorgestuurd. "Niets om je zorgen over te maken" is de korte samenvatting van mijn e-mail communicatie met de Hallmark Helpdesk. En hoewel ik drie mailtjes heb gestuurd, zijn ze alle drie even vriendelijk beantwoord geweest.

En niet onbelangrijk. Ze hadden nog gelijk ook. Het is helemaal niet nodig om je zorgen te maken. De applicatie gaf onderaan aan dat ik allemaal foto’s van goede kwaliteit had gebruikt en de kalender is inderdaad ongelooflijk goed…



Zonet een verjaardagskalender besteld via Hallmark’s FotoFun applicatie. Bedoeld als cadeau. Maar het ding heeft slechts 3MB geupload. 3MB voor 35 foto’s die in de kalender verwerkt zijn…

Akkoord, die foto’s zulllen verkleind worden, maar ik stel me serieus de vraag of ze niet net iets te erg verkleind zijn…

Toch maar even de vraag gesteld. En dan hopen dat de kwaliteit toch redelijk goed is.