Turnaround/ Solution to duplicate keys in a Hash
sorted_words = Hash.new(0)
words.each { |word| sorted_words[word]=word.downcase.chars.sort{ |a, b| a.casecmp(b) }.join

require 'pp'
require 'set'

words = %w[cream scream scream creams]

hash = Hash.new{ |h,k| h[k] = Set.new }

words.each do |w|
  hash[w.downcase.split('').sort] << w.downcase
end

pp hash

=> {["a", "c", "e", "m", "r"]=>#<Set: {"cream"}>,
 ["a", "c", "e", "m", "r", "s"]=>#<Set: {"scream", "creams"}>}

puts hash['creams'.downcase.split('').sort].to_a.join(', ')

scream, creams

require 'pp'
require 'set'

words = %w[cream creams scream scream]

hash = Hash.new{ |h,k| h[k] = [] }

words.each do |w|
  hash[w.downcase.split('').sort] << w.downcase
end

pp hash

=> {["a", "c", "e", "m", "r"]=>["cream"],
 ["a", "c", "e", "m", "r", "s"]=>["creams", "scream", "scream"]}

puts hash['creams'.downcase.split('').sort].to_a.sort.join(', ')

=> creams, scream, scream