- There are some essential terms you need to know while working with JK levels.

**Sector**- A sector is basically a room made up of vertices, edges, and surfaces.

**Surface**- A surface is one side of a sector, a flat shape (like a wall of a room), made up of vertices and edges.

**Edge**- An edge is where two surfaces meet and is represented by a line drawn between two vertices.

**Vertex**- A vertex is a single point, like a period on this page, that connects edges and makes angles possible.Objects in red are defined below each image.

Sector

Surface

Vertex

Edge