In 1957, Kotzig proved that the line graph of a snark (non edge-3-colorable cubic graph) is a 4-coloring-snark (non edge-4-colorable 4-regular graph). In this paper we present a reverse construction, i.e., we construct snarks from 4-coloring-snarks. In a similar way, we construct graphs without nowhere-zero 3-flows from snarks.
