$ gforth
    Gforth 0.7.3, Copyright (C) 1995-2008 Free Software Foundation, Inc.
    Gforth comes with ABSOLUTELY NO WARRANTY; for details type `license'
    Type `bye' to exit
    s" rabbithole" .s" forth" .s" into" .s" deep" .s" too" .s" go" .s" not" .s" must" . 
    :1: Undefined word
    s" rabbithole" >>>.s"<<< forth" .s" into" .s" deep" .s" too" .s" go" .s" not" .s" must" .
    Backtrace:
    $7F53D6EF5A68 throw 
    $7F53D6F0BDB0 no.extensions 
    $7F53D6EF5D28 interpreter-notfound1                                           ::
    : ws s" rabbithole " s" forth " s" into " s" deep " s" too " s" go " s" not "  compiled
    s" must " 8 0 do type loop ;  ok
    ws must not go too deep into forth rabbithole  ok