[css] How can I get a Bootstrap column to span multiple rows?

I believe the part regarding how to span rows has been answered thoroughly (i.e. by nesting rows), but I also ran into the issue of my nested rows not filling their container. While flexbox and negative margins are an option, a much easier solution is to use the predefined h-50 class on the row containing boxes 2, 3, 4, and 5.

Note: I am using Bootstrap-4, I just wanted to share because I ran into the same problem and found this to be a more elegant solution :)