Hole
Holes occur through natural and artificial processes, and may be useful for various purposes, or may represent a problem needing to be addressed in many fields of engineering.
Holes can occur for a number of reasons, including natural processes and intentional actions by humans or animals.
The deepest hole on Earth is the man-made Kola Superdeep Borehole, with a true vertical drill-depth of more than 7.5 miles (12 kilometers), which is only a fraction of the nearly 4,000 mile (6,400 kilometer) distance to the center of the Earth.
Homology groups were originally defined in algebraic topology, and homology was originally a rigorous mathematical method for defining and categorizing holes in a mathematical object called a manifold.
The initial motivation for defining homology groups was the observation that two shapes can be distinguished by examining their holes.
[5] For surfaces a notion closer to the intuitive meaning exists: the genus of a connected, orientable surface is an integer representing the maximum number of cuttings along non-intersecting closed simple curves without rendering the resultant manifold disconnected.
One use of through holes in electronics is with through-hole technology, a mounting scheme involving the use of leads on the components that are inserted into holes drilled in printed circuit boards (PCB) and soldered to pads on the opposite side either by manual assembly (hand placement) or by the use of automated insertion mount machines.
Therefore, "[t]o avoid pinholes that might protrude through the entire thickness of the dielectric layer, it is a common practice to screen several layers of dielectric with drying and firing after each screening", thereby preventing the pinholes from becoming continuous.
[14][15] In the study of visual perception, a hole is a special case of figure-ground, because the ground region is entirely surrounded by the figure.
[18] Some people have an aversion to the sight of irregular patterns or clusters of small holes, a condition called trypophobia.
[19][20] Researchers hypothesize that this is the result of a biological revulsion that associates trypophobic shapes with danger or disease, and may therefore have an evolutionary basis.
[21][19] An example of the use of holes in popular culture can be found in the Beatles lyric from the song, "A Day in the Life", from their 1967 album Sgt.
[24] In art holes are sometimes referred to as negative space, as in the case of the Japanese concept of Ma.
If you are a religious person, you can explain the hole by saying that God put it there in order to make it easier for us to receive Him.
[28] As pictorial representations for emoji are platform-dependent, Emojipedia shows images of the hole symbol as depicted on various platforms.
