Feedback

Again, I'm not actually suggesting that you merge this in and remove all your code. This just makes it easier to leave feedback :smile: 

Please submit a help request for any questions that you have about my comments.

### Don't merge this pull request
When you do `(left..right)` you might be missing out on some important points. For instance, if left is 10 and right is 20, you're going to get back all the whole number integers between 10 and 20, which wouldn't include 15.5.

Using more simple comparison operators will help avoid this issue:

```ruby
  def contains_point?(x, y)
    x >= left && x <= right && y >= bottom && y <= top
  end
```