add tracking rules

systems.tex

@@ -120,6 +120,14 @@ If the \glspl{pc} fail the roll, the \gls{gm} should increase the \gls{tn} for a
 
 Once out, all penalties vanish, except for a single \gls{fatigue}.
 
+\makeRule{tracking}{Tracking}{Wits}{Wyldcrafting}{12}
+Excessive snow or rain means the \gls{tn} decreases by 2 due to mud or snow remembering every step.
+However, it also increases the \gls{tn} by 2 each \gls{interval}.
+\index{Tracking}
+
+Both the hunter and the hunted determine their rate of travel.
+The hunter continues making roll until they catch their quarry or lose them.
+
 \makeRule{walk_underground}{Walking Underground}{Dexterity}{Caving}{8, plus 2 per mile}
 Caverns offer all manner of impediments, from sudden drops to falling debris, and passages full of water.
 Each mile covered inflicts \pgls{fatigue}, as usual.