Talking about relativity

Talking about concepts ; talking about geometry ; talking about algebra ; variables, operators, functions ; pontificating about events ; the queen and the captain of the guard ; particles, world lines and the arrow of time ; the Mary Jane and the Penelope ; time ; the line-element and curvature of a surface ; the line-element and curvature of a space-time ; tensors ; the field equations ; from general to special ; particles in collision.