Reversing any two dimensionswill describe a completely different unit. Using the sameexample stated as 4x8x16 would indicate a unit 4 inches wideand 8 inches high (not 8 inches wide and 4 inches high).
Many water fleas swimming together. The water flea is a microscopic crustacean (around .2-5 mm long) that lives in lakes, ponds, swamps, and streams. The most common kind of water flea is the Daphnia. This little, translucent insect is named for the way it swims.
Fuel fleas. Fuel fleas are microscopic hot particles of new or spent nuclear fuel. While small, they tend to be intensely radioactive. The fuel particles, the size about 10 micrometers, are a strong source of beta and gamma radiation and a weaker source of alpha radiation.