words = %w(A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE) << ""
words.each do |word|
blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
res = word.each_char.all?{|c| blocks.sub!(/\w?#{c}\w?/i, "")} #regexps can be interpolated like strings
puts "#{word.inspect}: #{res}"
end