Platonic solids

"In Euclidean geometry, a Platonic solid is a regular, convex polyhedron with congruent faces of regular polygons and the same number of faces meeting at each vertex. Five solids meet those criteria, and each is named after its number of faces.
Geometers have studied the mathematical beauty and symmetry of the Platonic solids for thousands of years. They are named for the ancient Greek philosopher Plato who theorized in his dialogue, the Timaeus, that the classical elements were made of these regular solids." [Platonic solid. Wikipedia]
The geometry diagram example "Platonic solid" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Mathematics solution from the Science and Education area of ConceptDraw Solution Park.

The vector stencils library "Solid geometry" contains 15 shapes of solid geometric figures.
"In mathematics, solid geometry was the traditional name for the geometry of three-dimensional Euclidean space - for practical purposes the kind of space we live in. It was developed following the development of plane geometry. Stereometry deals with the measurements of volumes of various solid figures including cylinder, circular cone, truncated cone, sphere, and prisms.
The Pythagoreans had dealt with the regular solids, but the pyramid, prism, cone and cylinder were not studied until the Platonists. Eudoxus established their measurement, proving the pyramid and cone to have one-third the volume of a prism and cylinder on the same base and of the same height, and was probably the discoverer of a proof that the volume of a sphere is proportional to the cube of its radius." [Solid geometry. Wikipedia]
The shapes example "Design elements - Solid geometry" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Mathematics solution from the Science and Education area of ConceptDraw Solution Park.

The vector stencils library "Transmission paths" contains 43 symbols of power transmission paths, electronic circuits, bus connectors and elbows, terminals, junctions, and concentrators.
Use it to annotate electrical diagrams, electronic schematics and circuit diagrams.
"A physical medium in data communications is the transmission path over which a signal propagates.
Many transmission media are used as communications channel.
For telecommunications purposes in the United States, Federal Standard 1037C, transmission media are classified as one of the following:
(1) Guided (or bounded) - waves are guided along a solid medium such as a transmission line.
(2) Wireless (or unguided) - transmission and reception are achieved by means of an antenna.
One of the most common physical medias used in networking is copper wire. Copper wire to carry signals to long distances using relatively low amounts of power. The unshielded twisted pair (UTP) is eight strands of copper wire, organized into four pairs.
Another example of a physical medium is optical fiber, which has emerged as the most commonly used transmission medium for long-distance communications. Optical fiber is a thin strand of glass that guides light along its length.
Multimode and single mode are two types of commonly used optical fiber. Multimode fiber uses LEDs as the light source and can carry signals over shorter distances, about 2 kilometers. Single mode can carry signals over distances of tens of miles.
Wireless media may carry surface waves or skywaves, either longitudinally or transversely, and are so classified.
In both communications, communication is in the form of electromagnetic waves. With guided transmission media, the waves are guided along a physical path; examples of guided media include phone lines, twisted pair cables, coaxial cables, and optical fibers. Unguided transmission media are methods that allow the transmission of data without the use of physical means to define the path it takes. Examples of this include microwave, radio or infrared. Unguided media provide a means for transmitting electromagnetic waves but do not guide them; examples are propagation through air, vacuum and seawater.
The term direct link is used to refer to the transmission path between two devices in which signals propagate directly from transmitters to receivers with no intermediate devices, other than amplifiers or repeaters used to increase signal strength. This term can apply to both guided and unguided media.
A transmission may be simplex, half-duplex, or full-duplex.
In simplex transmission, signals are transmitted in only one direction; one station is a transmitter and the other is the receiver. In the half-duplex operation, both stations may transmit, but only one at a time. In full duplex operation, both stations may transmit simultaneously. In the latter case, the medium is carrying signals in both directions at same time." [Transmission medium. Wikipedia]
The shapes example "Design elements - Transmission paths" was drawn using the ConceptDraw PRO diagramming and vector drawing software extended with the Electrical Engineering solution from the Engineering area of ConceptDraw Solution Park.