gluPartialDisk - draw	an arc of a disk

	  void gluPartialDisk( GLUquadric* quad,
			       GLdouble	inner,
			       GLdouble	outer,
			       GLint slices,
			       GLint loops,
			       GLdouble	start,
			       GLdouble	sweep )

	  quad	  Specifies a quadrics object (created with

	  inner	  Specifies the	inner radius of	the partial disk (can
		  be 0).

	  outer	  Specifies the	outer radius of	the partial disk.

	  slices  Specifies the	number of subdivisions around the z

	  loops	  Specifies the	number of concentric rings about the
		  origin into which the	partial	disk is	subdivided.

	  start	  Specifies the	starting angle,	in degrees, of the
		  disk portion.

	  sweep	  Specifies the	sweep angle, in	degrees, of the	disk

	  gluPartialDisk renders a partial disk	on the z=0 plane. A
	  partial disk is similar to a full disk, except that only the
	  subset of the	disk from start	through	start +	sweep is
	  included (where 0 degrees is along the +y axis, 90 degrees
	  along	the +x axis, 180 along the -y axis, and	270 along the
	  -x axis).

	  The partial disk has a radius	of outer, and contains a
	  concentric circular hole with	a radius of inner. If inner is
	  0, then no hole is generated.	The partial disk is subdivided
	  around the z axis into slices	(like pizza slices), and also
	  about	the z axis into	rings (as specified by slices and
	  loops, respectively).

	  With respect to orientation, the +z side of the partial disk
	  is considered	to be outside (see gluQuadricOrientation).
	  This means that if the orientation is	set to GLU_OUTSIDE,
	  then any normals generated point along the +z	axis.
	  Otherwise, they point	along the -z axis.

	  If texturing is turned on (with gluQuadricTexture), texture
	  coordinates are generated linearly such that where r=outer,
	  the value at (r, 0, 0) is (1.0, 0.5),	at (0, r, 0) it	is
	  (0.5,	1.0), at (-r, 0, 0) it is (0.0,	0.5), and at (0, -r,
	  0) it	is (0.5, 0.0).

	  gluCylinder, gluDisk,	gluNewQuadric, gluQuadricOrientation,
	  gluQuadricTexture, gluSphere