House plans with curved spaces include everything from circular staircases, bowed windows, barrel-vaulted ceilings, and archways. If you are ready to think outside the box, you may want to consider a house plan with curved spaces. A tall arched portico entry paired with vertical siding and a red front door creates an ideal modern farmhouse exterior. Eyebrow dormers with a stucco and stone exterior create a timeless European facade. Add arched garage doors or an arched entry porch framed in columns for a simple country exterior.