text: Though not exhaustive, we've covered most of the principles seen operating in the existing classical molds. In addition to what we've noted, there are two apparently redundant relationships that are consistently seen in the molds that are believed to have been made before 1700. First namely, in all these molds the line of the lower bout vesici occurs 1/5 along the length of the Body, variously calculating from the outline or the mold line. And second, the upper corner line corresponds with 1/4 the distance from the upper bout line down to the lower bout line. Sometimes a 2/5 distance is seen.
  We can uncover the system of geometry and ratios behind classical making, but how did they go about using and applying this system?
  Even after we understand the geometry behind a scroll, or an f hole, we still don't necessarily know how they made use of that geometry. Did they use a compass directly on the instrument as they carved? Or did they prepare the shape on paper and then use a template to apply the shape as they worked the wood? Did all the workmen understand the geometry, or just the master?
  And which shapes did they construct first? We know they took the sizing of the next part as a ratio of a previous part, so the sequence of working can matter.
  These kinds of questions can actually be harder to work out than it was to uncover the geometry. To some extent, we may never be able to unravel all of these kinds of details. For one, the sequence of work doesn't necessarily leave any evidence, particularly if the work is clean and symmetrical.
  But in many cases, there are clues and hints that tell us that one shape or size is dependent on another. When this dependency is clear, it strongly suggests that the dependent element was created after the element it depends on.
  And sometimes the classical variations in method gives some clue about the sequence of work. For example on the molds, the corner block lengths are normally set as a proportion of the distance from the bout line to the corner line. In itself, this suggests that both those lines are established before the block length is set. But in some cases, the makers set the length of the top corner blocks by just following the length of the lower corner blocks. In all cases, the lower corner block lengths are found by some kind of ratio, but in these few cases the upper blocks merely follows the lower block example. This implies that the lower blocks were worked out first, then the upper blocks were worked out after.
  There are cases of concrete sequence evidence in the working of the molds, and some less concrete cases. All these bits of evidence seem to suggest the molds were mostly worked from the bottom up. Also, the bout ratios tend to depend on the body length choice. And, the circle geometry for the outline curve of the mold in the center bout depends on the exact placement of the corner blocks. When we take all these bits of evidence together, there is a suggestive but not conclusive case for the sequence of work in these classical molds.
  First, a center line is scribed and a body length is set. Everything else depends on this choice. Then a plan for the bout ratios is made. The lower bout line is drawn at the 1/5 Body mark (calculated either by outline or mold line). Then the lower vesici are constructed on this line, following the planned bout ratios. The length of the long arc joining the vesici is chosen to reconcile the bout line to the planned body length. After the lower vesici are scribed, the lower corner line is scribed on a 2/5 Body mark. And the secondary block line (setting the lower corner block lengths) is set by proportion, generally on the 1/3 mark from from bout line to corner line. The corners must also be set horizontally. We haven't mentioned this before, but these are usually set on an arc drawn up from the bout line.
  Continuing the work from the bottom up, we can set the width of the center bout by planned ratio. Now we set the upper corner line using a 3 by 4 ratio from the top of the Body length and using the planned upper bout ratios. We can now place the upper bout line in relation to the upper corner line. Following the relationship seen in most all the earlier molds (pre 1700), we take 1/3 the distance from the upper corner line down to the lower bout line, and we place the upper bout line that distance above the upper corner line. The upper vesici are now scribed on this line following the bout plan. As with the lower bout, the radius of the long joining arc is selected to reconcile the upper vesici to the planned body length. Again, the corners are set horizontally by drawing a cut off arc based on the upper bout line.
  To finish the mold geometry, we need only work the curve for the center bout. For this, we take 1/2 the lower bout width as radius for the main center bout circles. The main circle is drawn to give the planned center bout ratios, and touching the planned corner notch (either upper or lower). We then use tangential corner circles of 1/4 and 1/5 radius for the lower and upper corners to complete the curve shape into the corners. Using the same 1/4 radius for the outer corner circles, we then draw up appropriate risers from the bout lines into the corners.
  Lastly, we calculate the main rib height as 8/10 of 1/9 the Body length and mark a corresponding guide arc onto the mold. One way to find the secondary rib height is to reduce the main rib height by 2 purfling widths. Nominally, this can be taken as 2/3 of 1/10 of 1/9 the Body length.
  Was this work done on paper first, or straight onto a board for a mold? Perhaps an effective method, particularly for a new original model, would be to work an outline geometry on the back board for an instrument. Then use paper to transfer the body length and bout width choices to a board for a mold?