Update ch-1.pl

1 files changed, 14 insertions, 12 deletions

diff --git a/challenge-124/james-smith/perl/ch-1.pl b/challenge-124/james-smith/perl/ch-1.pl
index 34cdf2cd64..4340825447 100644
--- a/challenge-124/james-smith/perl/ch-1.pl
+++ b/challenge-124/james-smith/perl/ch-1.pl
@@ -16,6 +16,7 @@ my $cross  = @ARGV ? shift @ARGV : $radius;
    $cross++ if $cross&1;
 
 ### A simple one to render the cross as drawin the question...
+### This is what we show if the radius (first parameter is 0)
 
 unless($radius) {
   my @pts = qw(-1 3 4 5 5 5 5 5 4 3 -1 0 0 0 -1 0 0);
@@ -32,21 +33,22 @@ unless($radius) {
 my @a = map { ' ' x ($radius*2+1) } 0..$radius*2+$cross;
 
 ## Now we draw the circle...
-foreach my $x (0 .. ceil($radius*0.71)) {
-  my $y = int sqrt( ($radius-.5)**2 - $x**2 );
-  substr $a[ $radius - $x ],$radius-$y,1,'^';
-  substr $a[ $radius + $x ],$radius-$y,1,'^';
-  substr $a[ $radius - $x ],$radius+$y,1,'^';
-  substr $a[ $radius + $x ],$radius+$y,1,'^';
-  substr $a[ $radius - $y ],$radius-$x,1,'^';
-  substr $a[ $radius + $y ],$radius-$x,1,'^';
-  substr $a[ $radius - $y ],$radius+$x,1,'^';
-  substr $a[ $radius + $y ],$radius+$x,1,'^';
+foreach my $x ( 0 .. ceil($radius*0.71) ) {      ## Only need to do 45 deg {X = r/sqrt(2)}
+  my $y = int sqrt( ($radius-.5)**2 - $x**2 );   ## Do a circle of radius r-.5 as we want
+                                                 ## to draw the mid point of the squares
+  substr $a[ $radius - $x ], $radius-$y, 1, '^'; # W -> NW
+  substr $a[ $radius + $x ], $radius-$y, 1, '^'; # W -> SW
+  substr $a[ $radius - $x ], $radius+$y, 1, '^'; # E -> NE
+  substr $a[ $radius + $x ], $radius+$y, 1, '^'; # E -> SE
+  substr $a[ $radius - $y ], $radius-$x, 1, '^'; # N -> NW
+  substr $a[ $radius + $y ], $radius-$x, 1, '^'; # S -> SW
+  substr $a[ $radius - $y ], $radius+$x, 1, '^'; # N -> NE
+  substr $a[ $radius + $y ], $radius+$x, 1, '^'; # S -> SE
 }
 
 ## And the two parts of the cross...
-substr $a[2*$radius+$_],$radius,1,'^' foreach 0..$cross;
-substr $a[2*$radius+$cross/2],$radius-$cross/2,$cross+1,'^'x($cross+1);
+substr $a[2*$radius+$_],       $radius,          1,        '^'             foreach 0..$cross;
+substr $a[2*$radius+$cross/2], $radius-$cross/2, $cross+1, '^' x ($cross+1);
 
 ### Finally we render the canvas...
 say $_ foreach @a;