>>>>> "M" == Mathieu Bouchard <matju / sympatico.ca> writes: M> a=[7]; a<<a M> b=[7,[7]]; b[1]<<b M> a==b pigeon% ruby require 'tangle' a=[7]; a<<a b=[7,[7]]; b[1]<<b p a == b -:4:in `==': detected recursive container object (TypeError) from -:4 pigeon% This is what you are looking with Christoph Rippel <crippel / primenet.com> tangle is on moulon, if you want try it. Guy Decoux