Client: I need a software to calculate the numbers of lottery
Programmer: Oh, but it's impossible!
Client: No, it isn't! I have all the idea on my mind.
Programmer: Do you know the probability?
Client: Oh, yeah. I have some formulas on my mind... It's very simple...
Programmer: There are billions of combinations!
Client: I have the formulas. I only need someone to code it...
Programmer: Ok. If you want a program, I can code a program...
Client: Great. So I'll pay you with 10% of the prize!