To achieve symmetry in your window design, draw an imaginary line down the center axis of your Tiny House RV. We’ve given you 2 examples. The Tumbleweed Elm has a centerline in the exact center of the house with the windows on either side of the center line; a mirror image of each other. Everting is symmetrical.
“You can also have a near or approximate symmetry in your design. Here there is no mirror image, but the masses placed on one side of the axis are roughly copied on the other side. There may be side extension that is different than its cousin on the other side, but they are of similar shape and size.” Source
However, The Tumbleweed Cypress is an example of approximate symmetry. In order to counteract the asymmetry of the door placement, a hip dormer is centered over the bay windows. Therefore, the window design is not a mirror image along the center axis, but the visual weight is counterbalanced by the doorway and dormer symmetry.