Draw a horizontal rectangle

Hello,

I'm new to Omnigraffle. I'm trying to draw a horizontal rectangle, which is
easy to do. What I'm not able to figure out is how I can make that
rectangle horizontal.

I need two rectangles above each other, and one of those will have
4-partitions. I just want to show that in the above level, I have a solid
rectangle, and the next level, it is separated in 4-regions. So, I just
need to make that look horizontal to demonstrate the idea.

Any ideas on how to make this horizontal move?

Thanks.