>>286 Ruby

puts "Hello, World!\n".codepoints.unshift(0).each_cons(2).map{|a, b| '%s.' % ((b > a ? ?+ : ?-) * (b - a).abs)}*''

# =>
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.
+++++++++++++++++++++++++++++.+++++++..+++.[略]