Designing in landscape with Storyboards

Is it possible to design interfaces in landscape with Interface Builder? Others with the same question apparently were able to do so with an arrow at the top right of any selected view, but I see no such arrow. A picture would be helpful. (Note: I am using storyboards, not xibs.)

Select the window in the storyboard, and open its Simulated Metrics property page (upper-right corner, an icon that looks like a shield next to the ruler icon). If the Simulated Metrics group is collapsed, expand it by clicking the black triangle to its left. There you will find an Orientation property; set it to Landscape.

The answer is correct, but I like a visual:

The answers above got me the answer, but I needed another step in Xcode 5. Instead of just clicking on my GLKView, I needed to select the GLKit View Controller property below the view. Then the Orientation appeared in the Attributes Inspector.

For Xcode 8 - Click the View As text at the bottom of the storyboard: