Vector, not raster
Raster displays draw every dot in a grid, 60 times a second. Vector displays draw only the lines they need — the electron beam traces the geometry directly. The result is razor-sharp at any scale, with a glowing, cinematic quality. Atari's Battlezone, Asteroids, Tempest and Star Wars all used vector hardware.
Tempest's radial tunnel
Designed by Dave Theurer, Tempest places the player at the edge of a web-like tunnel viewed from above. Enemies crawl up the lanes toward you. The entire screen is radial lines and angles — an aesthetic that would be impossible on raster hardware of the era and eerily similar to a Plan Position Indicator radar display. The colour overlay added psychedelic flavour to the monochrome vectors.
Star Castle's concentric rings
Cinematronics' 1980 classic encloses the player in rotating rings of shields that must be chipped away to reach the core cannon. The rings glow with phosphor persistence, breaking apart in geometric shards. The whole game is a radar screen turned into fortress.
The legacy in modern UI
Every neon wireframe, every HUD reticle, every sci-fi radar display in games from Elite Dangerous to Homeworld owes something to the vector arcade era. The aesthetic of glowing lines on black is synonymous with 'radar' and 'space' because Tempest and Star Castle burned it into popular culture.