Free old harbour in Lüneburg, Germany image, public domain CC0 photo. https://www.rawpixel.com/image/5909467/image-background-public-domain-freeFree Image from public domain licenseAbstract skyscraper symmetry in black and white. Free public domain CC0 photo. https://www.rawpixel.com/image/6028823/photo-image-public-domain-abstract-patternFree Image from public domain licenseApple iPhone, digital device photo, location unknown, 30 September 2019. https://www.rawpixel.com/image/6113710/photo-image-iphone-phone-public-domainFree Image from public domain licenseVacation hut, Alpine lake, Switzerland. Free public domain CC0 photo. https://www.rawpixel.com/image/6021243/photo-image-public-domain-mountains-freeFree Image from public domain license