Sunday, March 16, 2014

The Christmas Investigations - Adventure Game: Part Two

Christmas Investigations
Part Five
In our Christmas Investigation into The Adventure Game we visited Arg and tried to learn a little something about their culture, their ways of thinking and, most importantly, their currency. The task I set was a simple one:

How can you pay for your ticket home with the exact change.

If you recall the Argond system of currency used twenty five different coins. Although I didn't show you every different available coin I made sure to show you the five different symbols, and five different colours which make up the currency. It shouldn't have been a big leap to realise that if each colour is paired with each shape once, you get the twenty-five different pieces stated in the puzzle.

A grid showing all of the different drogna. Five each of circle, crescent, triangle, square and pentagon. Each in a different colour from Red, Orange, Yellow, Green and Blue.

Here are the twenty five different coins which make up the currency on Arg, arranged in a logical order. This is important as working logically, as the Argonds would, is the only way to get your head around the currency.

We were implicitly told the value of four of the pieces in the puzzle, and told that two further pieces added up to the same value. 

This is our diagram updated with the information we have. You might have been looking for a simultaneous equation style method to solving this puzzle. That method just wont work since you have too many variables and not enough data. What you needed to do was work out the reasoning behind the numbering. In the UK we put a five on a bank note because it's worth five pounds and five is the symbol for 'five'. Why therefore is a green circle, a red square or an orange crescent the symbol for four?

If might not seem a lot, but if we take a few logical leaps we can come up with a reasonable solution. It should not have escaped your notice that the fourth item in the first column is worth four. Similarly the first item in the fourth row is worth four. However, the other four is the second item in the second column. 

In other words items 1x4, 4x1 and 2x2 are all fours. When you write it like that it seems obvious doesn't it. The value of a coin is its row multiplied by its column. Except, I chose the arrangement of the pieces in this grid, if I had swapped the crescents and the pentagons, or the blues and the greens it wouldn't work. So why is this arrangement the right one?

Well, the pieces are arranged in columns according to how many sides they have, indeed this is the first number you multiply to get the value. The pieces are also arranged in rainbow order and again, it is the position int he rainbow which you must multiply by to get the value. 

So to pay your thirty-three Drogna fair you need just proffer the blue square which is worth 16, the yellow triangle worth 9 and the orange square worth 8.
A Blue Square, A Yellow Triangle and an Orange Square make thirty-three.

That's not all the fun that can be had with the Argond currency mind you. So if you've enjoyed tackling the nuances if number and shape, then try and solve these problems.

What is the smallest value, greater than one, that cannot be made up from two Drogna?

What is the smallest value, greater than two, that cannot be made up from three Drogna?


  1. Hi David.

    I stumbled across these Christmas Investigations posts on the back of a search for "drogna" and wondered if I could pick your brains?

    Assuming you watched the show, or some of the "Challenge TV" re-runs, how do you remember the Drogna being constructed?

    Having done some research and contacted Ian Oliver, the show's original producer, he believes that they were 5mm clear acrylic, possibly around 60mm diameter, with the coloured shapes being slightly less to allow a gap between the shape and disc edge when the shape was affixed to to the centre of the clear disc.

    He also mentions that the edges were buffed to remove any sharpness, but not rounded off at all.

    My main concern is that I remember the coloured shapes as being slightly proud of the clear bases, or in other words, they were cut from thinner material, like 3mm sheet, and then glued to the "top" of the base. I noticed in your drawings that you show the shapes as having no depth, or "flat" and wondered if that was just the way you'd done them, or if that was indeed how you remember them?

    Do you have any inside information that you'd be willing to share or that I can check? With no DVDs available, the only on-line footage is quite poor quality and it's very hard to be 100% sure of the Drogna dimensions.

    I should say why I'm asking, and that is because I'm looking into the feasibility of producing "sets" of 5 or 25 Drogna to sell to fans of the show. I'd dearly love to have a set, and I know of a few other people at least who would too.

    Hoping you might be able to shed some light on the above for me.


  2. Sorry to take so long getting back to you, unfortunately my source material for Adventure Game is as limited as yours. If I was pushed I would say that the Drogna in the show were asymmetrical, in that the colour was applied on one side only, and they were usually placed with the other side face up.

    If you do go ahead with producing these I'd probably be interested too.

    Many Thanks, and sorry again for the delayed reply.


  3. Hi, I ended up giving up on it, as having contacted 5 companies who make exactly this sort of thing, only one replied and despite appearing interested, and us exchanging emails as we got nearer to a "how are we going to do this", they literally just stopped contacting me, or replying. *sigh*