Draw a triangle. Easy, right? Now try drawing a balbis. That might sound much harder—until you realize that you’ve actually been doing it since Kindergarten (keep reading). There are a number of shapes most of us come into contact with every day while blissfully unaware of what to actually call them.
The best-known example of this shape is the capital letter H. Mathematically, a “balbis” is defined as a single line that is terminated by a secondary line at each end, both of which are positioned at right angles to the primary line.
Like the oft-ridiculed “spork,” this shape’s name betrays its identity: it’s essentially a circle/square hybrid with properties of both. Lately, squircles have found widespread use in modern car designs.
A seven-pointed star which appears in the flags of Australia and the Cherokee Nation.
Also known as a “trefoil knot," triquetras are a staple of Celtic and early Christian art (sometimes drawn interlaced with a circle).
5. Star of Lakshmi
Another shape of religious significance, the eight points of this star represent the eight types of wealth provided by the goddess Lakshmi.
Two loops that meet at a central point form this shape, which has become the famous “infinity symbol.”
7. Vesica Piscis
In America, when something’s called “football-shaped,” this is generally what the person is talking about. One can create a vesica piscis by overlapping two circles with equal radiuses so that the edge of each one touches the others’ center. In this image, the vesica piscis itself is the lightly-shaded area between the two “crescent-moon” shapes.
Not to be confused with the sporting venue, a geometric “stadium” is a rectangle with a pair of semi-circles positioned at opposite ends.
A nine-sided polygon which inspired a catchy tune by They Might Be Giants. Temples of the Bahá'í faith are required to have a nonagonical outline.
Also known as the “Star of Goliath,” this nine-pointed star has been adopted as the logo of the popular heavy metal band Slipknot.
The technical term for a “ring shape,” an annulus is formed in the space between two concentric circles.
12. Reuleaux Triangle
Popularly used on guitar picks and trail route signs, this curvaceous triangle-like shape is named after German engineer Franz Reuleaux. For more details, skip to the 1:20-mark of this video from Numberphile: