<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">In my attempt to build a macro for drawing several level surfaces of a quadratic, I have succeeded in what looked<div>at first like the hardest parts: drawing a "cut-open" hyperboloid of one sheet and a "cut open" double cone.</div><div>These have both been implemented in macros which accept as arguments many of the parameters of the problem,</div><div>including coefficients in the quadratic, colors, grid sizes, and colors.</div><div><br></div><div>Now I am trying to do the same for a hyperboloid of two sheets.</div><div>I am taking the tack of defining each of the two sheets as the graph</div><div>of a function, defined in polar coordinates and using the "surface parametree"</div><div>object in pst3d-solides; this involves defining two functions (one for each sheet)</div><div>and two pstsolids. The attached code </div><div></div></body></html>