I often model things like walls and leaves with only one side. Most computer graphics tools I’ve dealt with only show geometry that faces the viewer. This puts one-sided surfaces in a predicament. When the viewer goes behind them, the geometry disappears.
One simple workaround to this problem is to duplicate your one-sided model and flip its normals to point the reverse direction. Facing one way, the viewer will see one model. Facing the other, the viewer will see the other model. Of course this duplicates geometry and leaves you in a brittle state. If you change the model, you have to change it’s counterpart. Oh, well.
Here’s how you might duplicate and flip in Blender: