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|Oscillator type||Babbling brook|
|Number of cells||16|
|Rotor type||Diagonal on-off|
|Year of discovery||Unknown|
Four boats (or hourglass) is a period 2 oscillator, which is composed of four boats in one of its phases. It has two diagonal on-off rotors enclosed by a common stator. While the two rotors are not connected, the stability of the stator still requires them to be in the same phase.
- Mark D. Niemiec. "Life objects sorted by name". Retrieved on April 30, 2009.
- Four boats at the Life Lexicon