Portals

Portals are the main game-play mechanic in the Portal series. Portals are placed by firing the Handheld Portal Device, they work in pairs where they allow two-way movement through each Portal. A player can place blue and orange portals in Singleplayer, or in Co-op: As Atlas, blue and cyan; and as P-body, red and orange. Lone portals appear as a solid-coloured oval and paired portals a colour-bordered oval - with the "center" being a window to the other Portal.

World Portals
Within certain levels there are World Portals (Brush entity, ). These are invisible portals that can be used to create the illusion of a larger area - for example,