How to reimplement the map method in ruby using recursion?

I'm a ruby newbie, learning to code. I wanted to understand how some of the methods available from the Enumerable module work. So I'm reimplementing them. One challenge was to implement them using recursion. However, I'm running into a problem when trying to implement the Enumerable#Map method using recursion.

This is my code:

class Array
  def mymap_recursive(&block)
    copy_of_array = dup
    new_array = []
    return new_array if copy_of_array.empty?
    value = copy_of_array.shift
    new_array << yield(value)
    copy_of_array.mymap_recursive(&block)
  end
end

I tried to figure out why it wasn't working so I put

puts "#{new_array}"

at the end of the method. Then in Sublime Text, I did

arr = [2,2,5,5,10]
arr.mymap_recursive {|n| n * n}

After pressing cmd+b, the output I got was:

[100]
[25]
[25]
[4]
[4]

I cannot figure out why its not returning one array with all the values.

Thanks for your help!