;; d
;;
(damping ,number? "Amount of beam slope damping.")
+ (dash-definition ,pair? "List of @code{dash-elements} defining the
+dash structure. Each @code{dash-element} has a starting t value,
+an ending t-value, a @code{dash-fraction}, and a @code{dash-period}.")
(dash-fraction ,number? "Size of the dashes, relative to
@code{dash-period}. Should be between @code{0.0} (no line) and
@code{1.0} (continuous line).")