Fixes in 2018/yang

Update .gitignore with files created by the commands in the README.md
(and some that can be with the right combinations that are not noted).

Typo and formatting fixes in README.md.

2018/yang/.gitignore

@@ -4,9 +4,10 @@ generated3.c
 generated4.c
 generated5.c
 left
-msg0
-msg1
-msg2
+msg[0-9]
 prog
 right
 shift
+rotated_counterclockwise.txt
+rotated_clockwise.txt
+no_leading_space.txt

2018/yang/README.md

@@ -39,15 +39,14 @@ this program left and recompiling will reveal other tools including a right rota
 and a shift program.
 
 Strange things happen when the world is upside down! It is entirely possible
-that this is remark is completely misleading.
+that this remark is completely misleading.
 
 What exactly does the shift program do?
 
-Like a great sliding puzzle (hint) this entry has 6 more programs that will
-reveal messages and one more tool that can be used to reveal the final
-message hidden in the original source.  All of these can be created using
-combinations of ./left, ./right and ./shift and the additionally generated
-programs.
+Like a great sliding puzzle (hint) this entry has six more programs that will
+reveal messages and one more tool that can be used to reveal the final message
+hidden in the original source.  All of these can be created using combinations
+of `./left`, `./right` and `./shift` and the additionally generated programs.
 
 The final message can be revealed using
 
@@ -55,12 +54,12 @@ The final message can be revealed using
 ./msg9 < prog.c
 ```
 
-But what combinations will generate ./msg3, ./msg4, ./msg5, ./msg6, ./msg7,
-./msg8 and finally ./msg9?
+But what combinations will generate `./msg3`, `./msg4`, `./msg5`, `./msg6`,
+`./msg7`, `./msg8` and finally `./msg9`?
 
 ## Author's comments:
 
-### Tools usage
+### Tools' usage:
 
 Nuko is a text rotator: given some text in stdin, Nuko will write the
 same text to stdout, but rotated 90 degrees counterclockwise.
@@ -108,7 +107,7 @@ Where this might be useful, besides ruining the formatting of certain
 files, is that it completes the set of tools needed to solve the
 puzzle that is embedded in prog.c
 
-### Puzzle box
+### Puzzle box:
 
 Notice how the edges of prog.c contain two notches.  By rotating
 prog.c and removing leading space, the code would be shifted one space
@@ -135,20 +134,20 @@ in prog.c, all you need is a C compiler.
 
 ### Features
 
-   - Code compiles when rotated 4 ways.  This required a bit of
-     patience to achieve.  Code still compiles even with one column of
-     text shifted.  This required even more patience.
+- Code compiles when rotated 4 ways.  This required a bit of patience to
+achieve.  Code still compiles even with one column of text shifted.  This
+required even more patience.
 
-   - All rotated and shifted variants compiles without warnings.  This
-     involves various tweaks to satisfy cases where compiler is overly
-     protective, including but not limited to the "1125" at line 4 as
-     opposed to "1025", to satisfy -Waggresive-loop-optimizations.
+- All rotated and shifted variants compiles without warnings.  This involves
+various tweaks to satisfy cases where compiler is overly protective, including
+but not limited to the "1125" at line 4 as opposed to "1025", to satisfy
+`-Waggresive-loop-optimizations`.
 
-   - CRC32 of the code is embedded in the code itself.
+- CRC32 of the code is embedded in the code itself.
 
-   - Process for writing prog.c is available in spoiler.html
+- Process for writing prog.c is available in spoiler.html
 
-### Compatibility
+### Compatibility:
 
 Nuko and the rotated tools accepts only ASCII files where each
 character maps to exactly one byte.  Also, end-of-line sequence is
@@ -158,18 +157,18 @@ will look weird after rotation, for example.
 
 Nuko has been verified to work with these compiler / OS combinations:
 
-   - gcc 4.8.4 on Linux
-   - gcc 4.9.2 on Linux
-   - gcc 6.1.0 on JS/Linux
-   - gcc 6.3.0 on Linux
-   - gcc 6.4.0 on Cygwin
-   - clang 3.5.0 on Linux
-   - clang 3.8.1 on Linux
-   - clang 5.0.1 on Cygwin
-   - tcc 0.9.25 on JS/Linux
+- gcc 4.8.4 on Linux
+- gcc 4.9.2 on Linux
+- gcc 6.1.0 on JS/Linux
+- gcc 6.3.0 on Linux
+- gcc 6.4.0 on Cygwin
+- clang 3.5.0 on Linux
+- clang 3.8.1 on Linux
+- clang 5.0.1 on Cygwin
+- tcc 0.9.25 on JS/Linux
 
 Nuko compiles without warnings with all compilers above, even with
-"-Wall -Wextra -pedantic" for gcc and clang.
+`-Wall -Wextra -pedantic` for gcc and clang.
 
 ## Copyright and CC BY-SA 4.0 License: