       SippBlock {xsize ysize zsize} shaderhandle [texture]
              Creates  a  square  block  with the size defined by
              xsize, zsize and zsize.  The surface is shaded with
              the  algorithm  and surface parameters specified by
              shaderhandle.  The block is centered about the ori-
              gin.

              Texture is the texture mapping algorithm to use for
              the object.  The NATURAL texture mapping is similar
              to  CYLINDRICAL  but  the x coordinate is not taken
              from projection on a cylinder but  is  evenly  dis-
              tributed  around the perimeter. An odd thing in all
              the 2D mappings (all except WORLD) for the block is
              that  the  top  face  will have texture coordinates
              (0.0, 1.0) while the bottom will get (0.0, 0.0).

              See  the  help  file  sipp/Texture-Map   for   more
              details.

              An  object handle that references the new object is
              returned.
