Subject: Re: [HM] rediscovered quartics
From: James A. Landau (JJJRLandau@aol.com)
Date: Wed Feb 09 2000 - 18:15:07 EST
You might check textbooks on computer graphics, such as Hill, Foley & van
Dam, or Hearn & Baker. Such books show how to go from "verbal/mechanical
descriptions" to "mathematical descriptions" that can then be easily
programmed. This may be backwards from what you want, though.
Here, from an old homework assignment, is the Pascal code for a 3-d figure
known as the "Starr beauty".
function starr (x, z: real) : real;
var x2, z2 : real;
begin
x2 := x * x;
z2 := z * z;
starr := x * z * (x2 - z2) / (x2 + z2);
end;
> the mechanical (i.e. verbal)description of these quartics (for the
> bohemian dome it starts "rotate a circle about another circle..."
Wouldn't "rotate a circle about another circle" give you a cycloid?
James A. Landau
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