>>>>> "K" == Keith Hodges <K.Hodges / ftel.co.uk> writes: K> class Null One small problem with your implementation is (your class is in null.rb) pigeon% cat b.rb #!/usr/bin/ruby require 'null' p 0 + NULL pigeon% pigeon% b.rb ./b.rb:3:in `+': coerce must return [x, y] (TypeError) from ./b.rb:3 pigeon% Guy Decoux