Explanation to the logic problem:
John was blind when he went to London. Paul was a doctor
who operated on him & cured him - hence his happiness.
On the way back, the train was in darkness in the tunnel,
John thought he was blind again, couldn't stand the
thought, so killed himself.
Logical, eh? You'll get lots of groans when you tell
the students or they eventually discover it through
There are more 'logic problems' in Challenge To
Think' by Rinvolincri, Frank & Berer (ELB Publishing)