>> alien = true
>> speaks_english = false

# 1
>> alien and speaks_english ? 'hello' : '**silence**'
=> "**silence**"

# 2
>> alien && speaks_english ? 'hello' : '**silence**'
=> "**silence**"

# 3
>> speaks_english and alien ? 'hello' : '**silence**'
=> false  # oops

# 4
>> speaks_english && alien ? 'hello' : '**silence**'
=> "**silence**"