The following development step inserted the rulers. This time, the push-your-luck element was not based on an absolute value to estimate,  but rather on the admitted error-range, which solved the problem of the values distribution among players. Having high-value cards, indeed, did not represent an advantage over player with lower-value cards, as what mattered was to hit the rightest value, without over – or under-estimation. The push-your-luck system was based on the amplitude of the used ruler: the wider it was, the lowest the points it conferred. 

– Leo Colovini –