Two students of Bayes were walking to the dojo one morning, and when they passed a newsagent, the senior of the two said to his friend "hold on a mo", and went in and bought a lottery ticket. As they continued their walk the junior student was frowning, and he went red with mental effort, and finally at the dojo gates he accosted his friend and said "I've been thinking and thinking and I can't see why the hell you bought that ticket. You know they're useless. I know you're not mad. Now I'm going mad. Explain yourself!". The older student cracked up laughing, and said "I have received what I paid for", before throwing the ticket in the bin and proceeding into class. The younger student was enlightened.