Fed by every robbery. When the clock dies: half to the last 5 robberies, equal shares; half to the 4 priciest plots, by price. Ties go to whoever got there first: a plot only enters the top 4 by beating the cheapest one in it, so the first four robberies of a season hold the spots until someone pays more. Then a new season starts: you keep your plots and their prices, only shields drop.
A pot that grows all season. Burn $ROB for a district, any district. When the season ends, the district that burned the most takes the whole pot, split equally over its owned plots, paid in that district's stock. No burns? It rolls over.
Burn 10,000 $ROB and your plot cannot be robbed for 2 hours. Use it to hold a top-4 plot until the clock dies. Shield burns do not count for the campfire. $ROB is never minted again.