require "rubygems"
require "ago"
require "chronic"

dif = ( 15 * 60 * 60 )
tf  = '%H:%M'
puts "Colombia | Australia"
0.upto 23 do |n|
  if n < 12
    l = 'am'
  elsif n == 12
    l = 'at noon'
  else
    l = 'pm'
  end
  time  = Chronic.parse( "#{ n } #{ l }" )
  ct    = time.strftime tf
  at    = ( time + 15.hours ).strftime tf
  puts "#{ ct }    | #{ at }"
end

# This is the output
Colombia | Australia
00:00    | 15:00
01:00    | 16:00
02:00    | 17:00
03:00    | 18:00
04:00    | 19:00
05:00    | 20:00
06:00    | 21:00
07:00    | 22:00
08:00    | 23:00
09:00    | 00:00
10:00    | 01:00
11:00    | 02:00
12:00    | 03:00
13:00    | 04:00
14:00    | 05:00
15:00    | 06:00
16:00    | 07:00
17:00    | 08:00
18:00    | 09:00
19:00    | 10:00
20:00    | 11:00
21:00    | 12:00
22:00    | 13:00
23:00    | 14:00