diff g/source/parse.h toroid-patch/parse.h
505a506
>   TOROIDAL_TOKEN, /* PoD */
diff g/source/parstxtr.c toroid-patch/parstxtr.c
1,2c1
< /****************************************************************************
< *                parstxtr.c
---
> /*                parstxtr.c
705a705,709
>        EXIT
>      END_CASE
> 
>      CASE (TOROIDAL_TOKEN)
>        New->Type = TOROIDAL_PATTERN;
diff g/source/pattern.c toroid-patch/pattern.c
72a73
> static DBL toroidal (VECTOR EPoint); /* PoD */
1312a1314,1332
> /* PoD */
> static DBL toroidal (VECTOR EPoint)
> {
>   register DBL value;
>   register DBL d2;
> 
>   /*distance from circle = sqrt( y*y + (sqrt(x*x+z*z)-1)*(sqrt(x*x+z*z)-1) )*/
>   /* thanks to John VanSickle and Peter Popov for the formula */
> 
>   d2 = sqrt(EPoint[X]*EPoint[X]+EPoint[Z]*EPoint[Z]) - 1.0;
>   if( fabs(EPoint[Y]) >= 1 || d2 >= 1.0 )
>       return(DBL)0;
>   value = sqrt( EPoint[Y]*EPoint[Y] + d2*d2 );
>   CLIP_DENSITY(value);
> 
>   return(value);
> }
> /* PoD */
> 
1465a1486
>     case TOROIDAL_PATTERN:   value = toroidal      (TPoint);      break;   /* PoD */
diff g/source/pattern.h toroid-patch/pattern.h
85c85
< 
---
> #define TOROIDAL_PATTERN        32 /* PoD */
diff g/source/tokenize.c toroid-patch/tokenize.c
517a518
>   {TOROIDAL_TOKEN, "toroidal"},