The possession by any person other than a public officer, as such, of any flag, standard, color, ensign, shield, or other insignia of the United States, or flag, ensign, great seal, or other insignia of this state, on which shall be anything made unlawful by this chapter, or of any article or substance or thing on which shall be anything made unlawful by this chapter, shall be presumptive evidence that the same is in violation of this chapter.
Iowa Code § 718A.5