I only now notice that https://en.wikipedia.org/wiki/Gateway_Arch#/media/File:Gateway_Arch_windows.... is clad in (many hundreds of) quadrilaterals, presumably all slightly different! This reminds me of the elliptical staircase and undulating bookshelf construction nightmares in Nathan Myrhvold's house|science museum, where every piece was individually water- jetted and mechanically keyed with a binary code. Except the Gateway Arch-itects had puny computers and no Computer Algebra! Another goodie from the wiki: On October 28, the arch was topped out <https://en.wikipedia.org/wiki/Topping_out> as then Vice President <https://en.wikipedia.org/wiki/Vice_President_of_the_United_States> Hubert Humphrey <https://en.wikipedia.org/wiki/Hubert_Humphrey> observed from a helicopter.[58] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Bryant-63> A Catholic priest and a rabbi prayed over the keystone,[32] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Duffy-35> a 10-short-ton (9.1 t), eight-foot-long (2.4 m) triangular section.[59] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Courant-64> It was slated to be inserted at 10:00 a.m. local time <https://en.wikipedia.org/wiki/Central_Time_Zone_(North_America)> but was done 30 minutes early[32] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Duffy-35> because thermal expansion <https://en.wikipedia.org/wiki/Thermal_expansion> had constricted the 8.5-foot (2.6 m) gap at the top[59] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Courant-64> by 5 inches (13 cm).[58] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Bryant-63> To mitigate this, workers used fire hoses to spray water on the surface of the south leg to cool it down[49] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Tribune-54>and make it contract.[58] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Bryant-63> The keystone was inserted in 13 minutes,[32] <https://en.wikipedia.org/wiki/Gateway_Arch#cite_note-Duffy-35> only 6 inches (15 cm) remained. For the next section, a hydraulic jack <https://en.wikipedia.org/wiki/Hydraulic_jack> had to pry apart the legs six feet (1.8 m). --rwg Also: Since 1965 (my graduation), US currency has inflated fourteenfold. "Seventeen Fifty Is Too Damned Much!" (MIT tuition "riot" chant.)