News & Articles The precise form of the Sfina Rokedet Shape

The precise form of the Sfina Rokedet Shape

In a previous article “Dancing Ship V or U?”we spoke about the shape of the Showbread according to the opinion of Rebi Yohanan and Rashi’s interpretation of how that looked, how it should more resemble a U shape than the V shape depicted in the Vilna Shas edition of the Talmud.

However, even Rashi’s drawing in the shape of a U is not sufficient to precisely define how the Sfina Rokedet (dancing-ship) shape looked.

To precisely define its structure it is necessary to combine the most ancient and authentic sources regarding this shape with modern technology, CAD engineering software to plot the exact dimensions of this shape so that it will reconcile with the geometry of the Shulchan (Table).

Let’s begin with the oldest existing source depicting this shape, the Pruta coin of Mattitya Antigonus II, the last of the Hasmonean kings (the king before Herod), from the period of the 2nd Temple.

On one side appears a picture of the Menora (Candelabra) and on the opposite side, a picture of the Showbread stacked on the Table. Regarding the authenticity of these coins refer to “A re-examination of the Showbread on the coins of Mattitya Antigonus”, Prof. Zohar Amar, Ma’alin Bekodesh, 21 Adar II, 2011. The table in the picture is most likely not the Shulchan (Table), but rather one of the other tables at the entrance to the Heichal (inner sanctum), upon which they stacked the breads prior to and after switching them on the Shulchan (Table).

From this it is clear that the shape of the base of the bread is curved and corresponds with the Sfina Rokedet (dancing-ship) shape of R. Yohanan. Obviously due to the limitations of the medium, this picture cannot be precise in every way and is intended as a “general” depiction encompassing the main features of the shape, but is not precise until the last millimeter!

The oldest written source describing this shape is from a Mishna (Menahot 11:5) –

Rebi Meir says the Table is 12 [tefachim] long and 6 [tefachim] wide. The Showbread is 10 [tefachim] long and 5 [tefachim] wide.  You place the [Showbread’s]  length across the width of the Table and fold it 2 [tefachim] on this side and 2 [tefachim] on this [other] side …..”.

A simplistic interpretation of this Mishna is probably the basis for the misconception that Maimonides ruled according to the opposing view – the Teiva Perutza (open-box) rectangular  shape (Hilchot Temidin Umusafim 5:9), as it may seem that the folding pattern mentioned here in the Mishna refers to right angled folds (90 degrees). However as we have shown (in the article “Did Maimonides Rule Teiva?”) that this is not necessarily the case and that he in fact did not side neither with R. Hanina nor R. Yohanan in this debate, or even refer to it at all, most probably because it was not relevant to the Halacha (ruling) and that either of them was acceptable.

In my subsequent description I will be assuming the method of Rebi Meir that 1 ama/cubit = 6 tefachim/handbreadths and that the thickness of the Showbread is 1 tefach/handbreadth (as stated in the Talmud, Tractate Pesachim 37a).

The Teiva Perutza shape is easily reconciled in the above description by the Mishna . Lay the bread with its length across the width of the Shulchan (Table) and fold the 2 tefachim/handbreadths that are sticking out, over the ends of the Table on either side, upwards at an angle of 90 degrees. The stack of 6 breads has a 12 tefachim/handbreadth height limit, so by stacking 6 breads, each 2 tefachim/handbreadths high, we comply with that limit.

It is possible to do the same for the Sfina Rokedet (dancing-ship) shape, but the folding angles and contours are not as simple as for the Teiva Perutza. For example, the base of the bread must be curved. What is the radius of that curve? In order for the 6 stacked breads to fit within the height limit of 12 tefachim/handbreadths, it is necessary for the breads to “overlap”, so that they fit within one another. How is this achieved and how much do they overlap?

There are no simple formulas for determining this and it was necessary to “fiddle” with the shape using a CAD (Computer Assisted Drawing) engineering program, over a period of two months! before we finally arrived at the solution.  It is (lehavdil) like a Mozart symphony that sounds simple and beautiful in hindsight, but extremely complex to compose or design.

We started with the shape of the Antigonus coin that gave us a general idea of how the bread would look.

We then started adding the constraints of the Mishna (above), that the length of the bread after folding fills the width of the Table (6 tefachim/handbreadths), that the flanks of the bread, folded up on the sides, have to have a flank length of 2 tefachim/handbreadths each. This enabled us to determine the radius of the base curve and also the folding angles of the upright flanks which we determined to be 97.74%

Following this we applied the constraint that the height of the stack of 6 breads could not exceed 12 tefachim/handbreadths and in order to do so it was necessary to taper the tops of the upright flanks to end in a sharp point, thus allowing the breads to sit one on each other, overlapping slightly in a seamless fashion.

Finally we had to account for the thickness of the “shelf” section of the snipim (uprights) which divided one bread from the other.

This is the final draft of the result –

This shape clarifies many of the aspects of the discussion in Menahot 94b that were not clear before, like the “sharp” edge of the flank of the bread and Rashi’s question – how do you lay pipes on such a sharp edge, etc.

It is a sobering thought that this effort took engineers, using the power of modern computing technology two months to fathom, while Rashi, almost 1000 years ago managed to decipher this in his minds’ eye.

 

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