primes = [2, 3, 5, 7]
puts primes[0..3] # => [2, 3, 5]
It actually outputs [2, 3, 5, 7]. I believe the author meant to write:
puts primes[0...3] # => [2, 3, 5]
Had trouble finding an email on his blog page. Hopefully the author is reading here.
def hello rescue end