perçage en serpentin

CONT: [...] Les perçages en arcs, en zigzag, en serpentin et en dents de scie, que la désignation suffit à expliquer [...] donnent à certains timbres un aspect spectaculaire [...]

OBS: scalloped roulette: A roulette in which the cutting blades are in the form of tiny arcs. All blades face the same way and are set in line so that the roulette is a series of concave arcs on one stamp and convex arcs on the adjoining stamp ...
OBS: ... it [rouletting] is further differentiated by the pattern of the cutting: serpentine, scalloped (or ""en arcs""), saw-toothed (or ""en scie""), straight-line (or ""en ligne""), etc.