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MAD, method of difficulty analysis

This is an extract from a paper presented at COET95 in New York titled 'Forgiving Folding'.

As a way of ranking or ordering models it would be convenient to have a measure of the relative difficulty of the location and manipulation of folds. In order to arrive at a measure I have estimated the time required on a trial basis by attempting the different types of locations in poor light. The actual manipulation difficulty I have used timed trials which I published in the BOS magazine in 1976. By including a nominal time for the actual fold of a valley/mountain and a time for orientation I have constructed a model of elements which are additive and give an indication of total difficulty. As a label for identification I have called this MAD, method of difficulty analysis. 

MAD folding difficulty measurements

 Coincidence Method 

2 locators on boundary 4 secs.

2 locators internal 6 secs.

4 locators 12 secs.

Crease method ( diagonal in half)

4 locators 16 secs


Mountain/valley 2 secs

Manipulation (secs extra after location and preliminary creasing)

Squash/reverse 8 secs Petal 17 secs Rabbit's ear 11 secs Sink 4 layers 39 secs Sink 8 layers 77 secs


Turnover/turn round 3 secs Unfold 2 secs

Let us see how the measurement of time difficulty applies to a traditional model. Here is the pecking crow .


For each step I count the seconds required for each type of activity ( some of you will recognise a similarity to time and motion study). Step 1 involves :Location 4, Crease 2, Unfold 2 a total of 8 (secs) Step 2 requires Location 16, Creases 8, total 24. and so on. The total nominal time for this model is 71 secs. Now the idea of the analysis is not only to rank models in order of difficulty but to see if improvements can be made. The first step is to see if any folds can be omitted, provided we use a stiff paper we do not need the blintzing. Next we can avoid the reverse fold by simply making a valley and mountain fold. The steps are now modified to make full use of boundary locations.

This is my reworking of the traditional model. Using the same nominal timing scales as before this now comes out at 34 secs. In addition my version has coloured wings which have to be drawn on the traditional model. I also believe that the beak on my version is more convincing than the traditional reverse.

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