Four bicyclists wearing helmets are racing along a city street while onlookers observe .
The bicyclists are sitting in the grass resting .
Four bicyclists wearing helmets are racing along a city street while onlookers observe.
The bicyclists are sitting in the grass resting.
The bicyclists cannot be sitting in the grass resting and racing at the same time.
The bicyclists can not be sitting in the grass resting and racing at the same time .