### shape | gap | hole | leak:

Venous leak
* can be a result of injury, disease, or damage to the veins in the penis.
* make it difficult for blood to remain in the penis during erection.

Water leak
* are costly and an unnecessary waste of water.
* can occur in such locations as pipes, valves, faucets, and drains.

Macular hole
* Most macular holes occur in the elderly.
* affect the central part of the retina.

Manhole
* are access points to pumping stations, valve vaults, and drainage systems
  - collection points for sewage and storm water and are gravity operated
  - how workers get from the streets to the systems underground
  - located in street corners
  - points of access to the sewer system for maintenance reasons
* provide access to sewers for maintenance.

Ozone hole
* Most ozone holes are part of stratosphere.
* Ozone Hole Learn how ozone shields Earth from harmful solar energy.
* are holes
* do exist and have been linked to higher skin cancer rates in Australia.
* occur generally in spring and can be very large.

### shape | gap | hole:

Pothole
* abound in the tops of Navajo Sandstone domes and smaller canyons.
* are also home to tiny desert animals.
* are an act of nature
  - important source of water for larger and smaller lifeforms
  - cavities
  - depressional wetlands found primarily in the upper Midwest
  - holes in the roadway that vary in size and shape
  - located in streets
  - more frequent during Texas winters
* are the direct consequence of vertical erosion and processes of abrasion
  - product of unrepaired cracks
* begin after snow or rain seeps into the soil below the road surface.
* can result from the continuous freeze-thaw cycle.
* come from a combination of traffic and water
  - in all shapes and sizes, with an equally varied array of lifespans
* exist in many parts of the country which have no gophers.
* fill and reflect the sky.
* left by glaciers fill with groundwater forming ponds and marshes.
* occur when moisture gets under the road material, such as through cracks in the surface
  - tires roll over small imperfections in the pavement, like a small ridge

Small hole
* can form nesting sites for birds such as wrens, wheatear and wagtails.
* found in beans indicate that they are infested with bugs.
* lead to underground runways and nesting areas.
* occur in very ripe fruit.

Stoma
* are aperture
  - located in leafs
  - orifices
  - part of colostomies
* have no sensation.
* is aperture

Weep hole
* allow visual inspection of seal condition.
* are teardrop-shaped drainage holes that are drilled into exposed conduit
  - usually easy to clean

### shape | gap | hole:

White hole
* are 'time reversed' black holes in general relativity.
  * are the exact opposites of black holes. A black holes sucks in energy and a white hole expels energy. They are polar opposites. Some scientists even believe you can make a wormhole if you connect a white hole and a black hole. Or, if you connected a white hole from the past, and connected it to a black hole today, you could theoretically create a time machine. The possibilities are endless
  - bizarre objects that are related to black holes

Wormhole
* are a direct consequence of general relativity
  - also a very powerful mathematical metaphor for teaching general relativity
  - junctions and are the only natural thing that let ships get between systems or maps
  - predicted by the theory of general relativity
* contain two mouths, with a throat connecting the two.