PREFIX log: <http://www.w3.org/2000/10/swap/log#>
PREFIX : <http://example.org/sample#>

:currentWeather a :NormalWeather.
:obs1 :ascribed :Rain.

() log:negativeSurface {
    :currentWeather a :NormalWeather.
    () log:negativeSurface {
        (_:S) log:negativeSurface {
            _:S :ascribed :Rain.
            () log:negativeSurface {
                _:S :ascribed :WetGrass.
            }.
        }.
    }.
}.

# query
(_:S _:O) log:querySurface {
    _:S :ascribed _:O.
}.
