Long ago, two prisoners escaped from neighboring facilities around the same time and in the same underground fashion. Fate allowed them to tunnel right into each other, which gave them quite a start. After sharing a good laugh, they bid each other adieu and continued digging their own tunnels in their own way, quite alone. Time passed, and once again their pick axes crossed. After another good laugh, the two suddenly realized that they could make more progress and build better passages if they had a go of it together, and that's what they did, happily ever after.