Complex sentence: The first US patent for a polyethylene plastic portable restroom was issued in the 1950s to Harvey Heather who was the founder of JW Enterprises and was called the "strong box"-a solid, molded, stand alone chemical toilet.
Split into simpler sentences: The first US patent for a polyethylene plastic portable toilet was issued in the 1950s to Harvey Heather, the founder of JW Enterprises. This "strong box" was a solid, molded, stand-alone chemical toilet.