The farmer was off to market with his fox, chicken and some grain. Times were hard after all. Upon reaching a river he positively had to cross on a boat so small that only he and one other could fit on he found himself puzzled.
“Eureka! I’ll take the chicken – the fox won’t eat the grain and I can return for them.”
Chicken safely deposited, he discovered on his return the fox had scarpered.
Taking the grain, on the other side, lo and behold, the chicken too had wandered off. “Drat,” the farmer mused, “why didn’t I drive?”.