Fix 2000/natori and add alt code

The author suggested alternate code for those in the southern hemisphere
which the natori.alt.c now has.

2000/natori/.gitignore

@@ -1 +1,2 @@
 natori
+natori.alt

2000/natori/Makefile

@@ -113,8 +113,8 @@ OBJ= ${PROG}.o
 DATA=
 TARGET= ${PROG}
 #
-ALT_OBJ=
+ALT_OBJ= ${PROG}.alt.o
-ALT_TARGET=
+ALT_TARGET= ${PROG}.alt
 
 
 #################

2000/natori/README.md

@@ -29,6 +29,20 @@ compile at all (gcc and clang respectively). Thank you Cody for your assistance!
 echo "Do or do not. There is no try."
 ```
 
+### Alternate code:
+
+The author noted that those in the southern hemisphere might want to change
+`acos(l/2)` into `acos(-l/2)`. Cody went ahead and made an alt version to do
+this.
+
+To run:
+
+```sh
+make alt
+```
+
+Use `natori.alt` as you would `natori`.
+
 ## Judges' remarks:
 
 Here is a nice compact program that changes with the phase of the moon.
@@ -46,8 +60,8 @@ This program outputs a rough image of the moon in its current phase.
 The main obfuscation of this entry is its complicated double recursion
 (without any loop or conditional statement).
 
-People living in the southern hemisphere may want to change acos(l/2)
+People living in the southern hemisphere may want to change `acos(l/2)`
-into acos(-l/2).
+into `acos(-l/2)`.
 
 ## Copyright and CC BY-SA 4.0 License:
 

2000/natori/natori.alt.c

@@ -0,0 +1,4 @@
+double l;
+int moon(int _, int o, int O){
+return putchar((_--+22&&_+44&&main(_,-43,_),_&&(int)o)?(main(-43,(int)++o,(int)O),((l=((int)o+21)/sqrt(3-(int)O*22-(int)O*(int)O),l*l<4&&(fabs(((time(0)-607728)%2551443)/405859.-4.7+acos(-l/2))<1.57))[" #"])):10);}
+main(int _,char**o,char**O){return moon(_, (int)o, (int)O); }