is($actual, $expected, $descriptionOfWhatYouTried);

   # to check effect of parameters passed to subroutine
   is(substr('abcdef', 0, 2), 'ab', q(tried subtr(..,0,2)});

   # to check what got captured by a regular expression
   is(eval { 'abcdef' =~ /^(\w+)/; $1 }, 'ab', q{tried /^\w+/});

##</code><code>##

not ok 1 - tried /^\w+/
#   Failed test 'tried /^\w+/'
#   in Monks/Snippet.pm at line 6.
#          got: 'abcdef'
#     expected: 'ab'
1..1
# Looks like you failed 1 test of 1.

##</code><code>##

   #changed is to isnt
   #This doesn't work. Captures 'abcdef' instead of just 'ab'

   isnt(eval { 'abcdef' =~ /^(\w+)/; $1 }, 'ab', q{tried /^\w+/});

##</code><code>##

#using perl MyExperiments.pl

ok 1 - using /(..)/
ok 2 - using /(.)\1/
ok 3 - using /((.)\1)/;$2
ok 4 - using /((.)\1)/;$1
ok 5 - using /(.)(\1+)/;"$1$2"
ok 6 - using /(..)/
ok 7 - using /(.)\1/
ok 8 - using /((.)\1)/;$2
ok 9 - using /((.)\1)/;$1
ok 10 - using /(.)(\1+)/;"$1$2"

#using prove MyExperiments.pl

MyExperiments.pl....ok
All tests successful.
Files=1, Tests=10,  0 wallclock secs ( 0.05 cusr +  0.04 csys =  0.09 CPU)

##</code><code>##

use strict;
use warnings;
use Test::More qw(no_plan);  #number of tests is constantly changing

#changed is to isnt:
#this doesn't work, results in 'ab'
isnt(eval {'abcdeee' =~ /(..)/;$1}, 'eee', q{using /(..)/});

#changed is to isnt:
#this printed out only 'e'
isnt(eval {'abcdeee' =~ /(.)\1/;$1}, 'eee', q{using /(.)\1/});

#changed is to isnt:
#this printed out undef
isnt(eval {'abcdeee' =~ /((.)\1)/;$2}, 'eee', q{using /((.)\1)/;$2});

#changed is to isnt:
#this also printed out undef
isnt(eval {'abcdeee' =~ /((.)\1)/;$1}, 'eee', q{using /((.)\1)/;$1});

#BINGO! this worked
is(eval {'abcdeee' =~ /(.)(\1+)/;"$1$2"}, 'eee', q{using /(.)(\1+)/;"$1$2"});

##</code><code>##

use strict;
use warnings;

#we have no plan!
#usually want to pick and choose tests anyway
#so the number is not fixed

use Test::More qw(no_plan);

#============================================================
# VARIOUS EXPERIEMENTS
#============================================================

#---------------------------------------------------
#GOAL: find run of repeating letters
#---------------------------------------------------

sub regexRepeat {
  my ($sInput, $sOutput) = @_;

  #-----------------------------------------
  # add tests here to try out different things
  # if it doesn't work, change is to isnt
  #------------------------------------------

  #changed is to isnt:
  #this doesn't work, $input='abcdeee' results in 'ab'
  isnt(eval {$sInput =~ /(..)/;$1}, $sOutput
       , q{using /(..)/});

  #changed is to isnt:
  #$input='abcdeee'  printed out only 'e'
  isnt(eval {$sInput =~ /(.)\1/;$1}, $sOutput
       , q{using /(.)\1/});

  #changed is to isnt:
  #$input='abcdeee' printed out undef
  isnt(eval {$sInput =~ /((.)\1)/;$2}, $sOutput
       , q{using /((.)\1)/;$2});

  #changed is to isnt:
  #$input='abcdee' also printed out undef
  isnt(eval {$sInput =~ /((.)\1)/;$1}, $sOutput
       , q{using /((.)\1)/;$1});


  #BINGO! this worked
  is(eval {$sInput =~ /(.)(\1+)/;"$1$2"}, $sOutput
     , q{using /(.)(\1+)/;"$1$2"});
}

#============================================================
# HERE IS WHERE I SELECT EXPERIMENTS
#============================================================

regexRepeat('abcdeeef', 'eee');   #only one to find
regexRepeat('abbb;eeef', 'bbb');  #should find first