In addition to the Goodyear STARAN computer, another tire company Firestone did built some interesting one off systems of unusual design. My first job out of college was with Firestone Central Research. While there, I became friends with William Clayton who was one of three of their research fellows. He was a big proponent of APL and there I was exposed to the MCM/700 (see https://www.softwarepreservation.org/projects/apl/Brochures/MCM700Brochure ) and the IBM 5100 desktop APL computer as well as APL via IBM 360 timeshare. We used APL to simulate the heat flow and rubber curing in very large earth mover tires with finite-element techniques coupled with chemical kinetics. However, Bill Clayton most interesting work was around optimizing formulations from designed experiment data. He built an analog computer that used static card readers that provided contacts to feedback resistors to simultaneous compute the output of 16 second order polynomial equations with cross terms for 8 independent variables. Each of these 16 polynomials had 54 static coefficients that were determined from second order statistical regressions of data from designed experiments. One equation for example might be tensile strength of a rubber compounded with various amounts of sulfur, carbon black, oil, accelerators, etc. Then another equation might represent wear resistance measured from the same combination of compounding ingredients. The 16 equations had upper and lower limits of acceptable values for tensile strength, wear, etc. The analog computer would then begin an exhaustive grid search of the 8 independent variables to find a combination of the 8 ingredients that met all 16 of the desired output traits. When a solution was found the independent variable value voltages were read by an A/D controlled by a PDP-8 and then printed on a console. Thus the system was actually a hybrid computer part analog and part digital. I was told that doing the 8 factor grid search in Fortran on an IBM 360/168 would have taken 1300 hours but this hybrid system did it in 5 minutes, Only three of these systems were ever built, two of which were used outside of Firestone (one by the Air Force). U.S. Patent 3,560,725 from 1968 provides some background as it covered an early version of the later more highly developed system. Mark