PEP-exported programs carry arc centers that are not equidistant from the
start and end points (e.g. I0.03 on a 0.0598 chord). Building the arc from
the end radius left its start off the previous move's end, so contours
failed to chain. Project the center onto the chord's perpendicular bisector.
The Draw Offset display offset each entity separately, which left spikes and
inverted loops wherever a feature is narrower than the spacing (1.nest,
P260417-06). Inflate the flattened region with Clipper instead, which
collapses narrow features and drops holes that close up.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>