+ penpos3 (w, angle (z2 - z1) + 90);
+ penpos4 (w, angle (z2 - z1));
+ penpos5 (v, angle (z1 - z2) + 90);
+ penpos6 (v, angle (z1 - z2));
+
+ fill z3r{z3r - z5l}
+ .. z4l
+ .. {z5r - z3l}z3l
+ .. z5r{z5r - z3l}
+ .. z6l
+ .. {z3r - z5l}z5l
+ .. cycle;
+enddef;
+
+
+%
+% Make a superellipsoid segment going from FROM to TO, with SUPERNESS.
+% Take superness = sqrt(2)/2 to get a circle segment.
+%
+% See Knuth, p. 267 and p.126.
+
+def super_curvelet (expr from, to, superness, dir) =
+ if dir = 1:
+ (superness [xpart to, xpart from],
+ superness [ypart from, ypart to]){to - from}
+ else:
+ (superness [xpart from, xpart to],
+ superness [ypart to, ypart from]){to - from}
+ fi