qr{(?smx)
    \.?   # Match the first instance of 0 or 1 one periods
    (     # then capture
     \S+  # one or more non whitespace characters
    )
  }

##</code><code>##

qr{(?smx)
   \.   # Find a full stop
   (.*) # and capture everything after it
  }

##</code><code>##

qr{(?smx)
  ^      # From the beginning
  (?:    # In a group...
   [^.]* # Match any character except period, any number of times 
   \.    # followed by a period
  )?     # math the group 0 or 1 times
  (.*)   # then capture everything else
  }