Updated rules and cover

After some feedback on a project i'm working on that features this system, i decided to add a rule. 

It worked fine before, but others made me notice that there were objectively better numbers to choose when guessing for a roll, and so that kinda defeated the purpose of it being a blind guess. 

The solution i came up with should patch this issue, giving an element of risk-reward to choosing certain numbers over others. 

plus, i decided to redraw the cover image because to me it was pretty rough looking, my style has kind of changed and this one was easy to remake. also, i like it better now uhuh.