- Equilateral triangle (Wikipedia)
In geometry, an equilateral triangle is a triangle in which all three sides have the same length. In the familiar Euclidean geometry, an equilateral triangle is also equiangular; that is, all three internal angles are also congruent to each other and are each 60°. It is also a regular polygon, so it is also referred to as a regular triangle.
- Bedrock (Wikipedia)
In geology, bedrock is solid rock that lies under loose material (regolith) within the crust of Earth or another terrestrial planet.