feat(rails): the wing rails of the frogs of the low section of the blades, as Zu1-60, where the timbers have slide chairs: from 1.5 m before the throat to their ends the foot raised as much as the blades ride, the web shortened, the heads level with the rails beside, forged down to the plain rail along 0.5 m; a wing rail which is the stock rail of a blade too, as in the slips with the blades outside of the diamond, whole along its chairs; the fastening holding only rails raised as much moved up on a pad as wide as it, a raised rail on a fastening with others on a pad of its own

world/Segment.h

@@ -48,6 +48,7 @@ struct loft_span {
     knots::line drops;
     glm::dvec2 head { 0.0 };
     double rise { 0.0 }; // how far the foot of the profile is raised, the web below the head (head.x) shortened by as much
+    knots::line rises; // along the span, in place of rise where given
 };
 
 struct segment_data {