On Friday 30 October 2009 09:29:16 pm Andy Burnett wrote: > What does the inner 'block' in [:n | [n]] actually do? A block is just a list of bytecodes - an anonymous method. When the 'value' message is sent to a block, the list is evaluated and the result is returned. In this case, the value of n (or n*10 in your second example). HTH .. Subbu