Alternatives
While wheels are very widely used for ground transport, there are alternatives, some of which are suitable for terrain where wheels are ineffective. Alternative methods for ground transport without wheels (wheel-less transport) include:
- Being raised by electromagnetic energy (maglev train and other vehicles)
- Dragging with runners (sled) or without (travois)
- Being raised by air pressure (hovercraft)
- Riding an animal such as a horse
- Human powered:
- Walking on one's own legs
- Being carried (litter/sedan chair or stretcher)
- A walking machine
- Caterpillar tracks (although it is still operated by wheels)
- Pedrail wheels, using aspects of both wheel and caterpillar track
- Spheres, as used by Dyson vacuum cleaners and hamster balls
Read more about this topic: Wheel
Famous quotes containing the word alternatives:
“Clearly, society has a tremendous stake in insisting on a woman’s natural fitness for the career of mother: the alternatives are all too expensive.”
—Ann Oakley (b. 1944)
“The last alternatives they face
Of face, without the life to save,
Being from all salvation weaned
A stag charged both at heel and head:
Who would come back is turned a fiend
Instructed by the fiery dead.”
—Allen Tate (1899–1979)
“The literal alternatives to [abortion] are suicide, motherhood, and, some would add, madness. Consequently, there is some confusion, discomfort, and cynicism greeting efforts to “find” or “emphasize” or “identify” alternatives to abortion.”
—Connie J. Downey (b. 1934)