They are very lightweight wrap-around sunglasses that cling lightly but securely to the temples, and totally occlude side glare.
Cylinder-shaped toys of 1-inch (2.5-cm) diameter (the size of a regular hot dog) are the most dangerous size because they can occlude the trachea (windpipe) if they are aspirated.
They also can seriously occlude your vision in dark dance halls, not to mention reduce your peripheral vision, both of which could prove disastrous in a fast-paced couples dance.
This swelling of the walls may partly or completely occlude the lumen of the vessels.
In many cases the colour-production is dependent on certain definite conditions - temperature, presence of oxygen, nature of the food-medium, &c. Ewart's important discovery that some of these lipochrome pigments occlude oxygen, while others do not, may have bearings on the facultative anaerobism of these organisms.