Storing array into another array, getting an unexpected result?

I'm totally new to Ruby. I came across something that I'm unable to explain.

Here is my code:

arr1 = []
arr2 = [0]

5.times{
  arr2[0] += 1
  arr1 << arr2
  }
puts "result = #{arr1}"

I was expecting the following result:

result = [[1],[2],[3],[4],[5]]

However, this is the result I'm getting:

result = [[5],[5],[5],[5],[5]]

Can someone explain to me why this happens? how I can fix it?

Many Thanks,