No. The film they showed my 8th grade science class (c. 1960) talked about the optimal shape for some kind of absorbency condition. However, that's very interesting. I find that optimal shapes with respect to interesting conditions can often be quite fascinating. I wonder how one might define the problem in a very simple way. It is striking that, for the actual shape, a) the usual shape given for an erythrocyte is a *solid of revolution*; b) the cross-section that is rotated is not a smooth curve, but is a continuous curve made up of several smooth arcs whose endpoints, but not derivatives, agree. —Dan ----- Perhaps this is what you recall? "Also, the biconcave shape allows RBC's to undergo extreme deformations while maintaining a constant surface area for gas exchange." Canham, P.B. "The minimum energy of bending as a possible explanation of the biconcave shape of the human red blood cell. J. Theoretical Biology, 1970. At 05:17 PM 10/12/2018, Dan Asimov wrote:

On this topic, I remember c. 8th grade being shown a film addressing this topic, that concluded the lenticular shape of the red blood cell — i.e., its hourglass cross==section — was exactly what some computer simulation shoowed was ideal (for exactly what conditions, I don't recall).

I later learned that the film was funded by a possibly biased organization, and even so I don't know if those claims stand the test of time (c. 58 years since 8th grade).

—Dan ----- ... why we had red blood cells ... ... -----