class Array

   def *(a)
       n    = Array.new
       [ alen = self.length, blen = a.length].max.
       times do |x|           
           n[x] = ( self[x] || 0 ) * ( a[x] || 0 )
       end

       n
   end

end 
#[ 2,4,4 ]  *  [ 5,5 ]
# =>[10,20,0]