Once there was a city who felt that their citizens were too short and wanted to do something about it. They tried all sorts of things until one day a traveling holy man came to the city and said his god could help. All the city folk needed to do was sacrifice tall people to his god and he would bless them with taller children.
The people were skeptical as no one would willingly sacrifice themselves and any method they could think of such as a lottery or vote would surely disadvantage people or be used by corrupt officials.
The holy man suggested that each person should have an equal chance as anyone else of being sacrificed according to their height. Thus once every year all the towns people would need to gather and roll the same holy 100 sided dice. On this dice were 3 marked sides corresponding to 160, 170 and 180 cm heights. If you rolled one of those sides and were taller than the side you were sacrificed.
Everyone agreed that this was a fair method and implimented it.
Decades latter the people wanted to know if the god they had been sacrificing the taller members of their society to had indeed blessed their city with taller children. Thus they took a sensis and measured everyone in the city. Sure enough the average height of the younger generation was taller than the older generation and records indicated that every year there were more younger people sacrificed per person than older people per person.
Thus it was deemed to be a success and proven beyond a shadow of a doubt that the city would be eventually filled with giants their mighty god was indeed real.