3.13.3.3 What is often misunderstood about the use of 'begin'
Robin Mair
One of the things people seem to have misunderstood is that in Dylan you only use a 'begin' "explicitly to limit the scope of a lexical variable, or in situations where a single expression is expected, such as an argument to a function call" - quoted from the Dylan Interim Reference Manual. So the 'begin' is very rarely seen.