One day Pablo and Paco are riding through the desert on their horses. As 
they ride along, Pablo smells something horrible. He stops his horse and 
turns around. He says "Hey Paco, you shit your pants?" Paco says "No, Pablo,
I did not shit my pants." He believes him and they keep riding. As they go 
on, the smell gets worse. The smell is so bad, flys begin to swarm. Pablo 
stops his horse and turns around. He then says "Paco, Are you sure you did 
not shit your pants?"  Pablo says "Yes Pablo, I am sure I did not shit my 
pants." He says "Ok." They keep going and now the smell is getting to be 
unbearable. Pablo is swatting the flys away. Pablo stops his horse and gets
 of his horse. He then says "Paco, get of your horse. Paco, pull down your 
pants. Paco, I thought you said you did not shit your pants?" Paco replies 
"I thought you meant today!"