// pattern for use in texture/pigment/normal/density
// various types of fractals
  // (---mandelbrot---)
  mandel 50               // number of iterations
         //2,             // optional exponent (2..4) [2]
  // (---julia---)
  julia <0.5,0.8>,        // complex number (2d vector)
        50                // number of iterations
        //2,              // optional exponent (2..4) [2]
  // (---magnet mandel---)
  magnet 1                // type (1 or 2)
   mandel 50              // number of iterations
  // (---magnet julia---)
  magnet 1                // type (1 or 2)
   julia <0.5,0.8>,       // complex number (2d vector)
         50               // number of iterations

  //exterior 1, 1         // optional: special handling of exterior
  //interior 0, 1         // optional: special handling of interior