| Interface | Description | 
|---|---|
| Area<T extends CellGame,U extends SpaceState<T,U,?>> | An Area is a pattern of SpaceObjects that can be generated and loaded by a
 SpaceState on demand. | 
| HUD | An HUD (heads-up display) renders visuals in front of those of the
 Viewports or SpaceStates to which it is assigned. | 
| SpaceLayer | A SpaceLayer renders visuals either in front of or behind those of the
 SpaceObjects in the SpaceStates to which it is assigned. | 
| Class | Description | 
|---|---|
| CircleHitbox | A CircleHitbox is a circular Hitbox with its origin at its center. | 
| ColorSpaceLayer | A ColorSpaceLayer is a type of SpaceLayer that fills the rendering region
 with a single Color. | 
| CompositeHitbox | A CompositeHitbox is a Hitbox that is composed of other Hitboxes whose
 positions, flipped statuses, and angles of rotation are all relative to those
 of the CompositeHitbox itself. | 
| DrawableSpaceLayer | A DrawableSpaceLayer is a type of SpaceLayer that displays a Drawable,
 optionally repeated horizontally and/or vertically across the rendering
 region. | 
| Hitbox | A Hitbox is a region of space that can be checked for intersection with
 other regions. | 
| LineHitbox | A LineHitbox is a Hitbox shaped like a line segment, with one endpoint
 being its position and the other being the sum of its position and a vector
 called its difference. | 
| MobileObject | A MobileObject is a SpaceObject that can simulate continuous movement
 through its SpaceState's space. | 
| PointHitbox | A PointHitbox is a Hitbox that consists only of the point that is its
 absolute position. | 
| PolygonHitbox | A PolygonHitbox is a polygonal Hitbox defined by a List of vertices. | 
| RectangleHitbox | A RectangleHitbox is a rectangular Hitbox with sides that remain
 orthogonal regardless of its angle of rotation. | 
| SpaceObject | A SpaceObject is a physical object in a SpaceState's space. | 
| SpaceState<T extends CellGame,U extends SpaceState<T,U,V>,V extends SpaceThinker<T,U,V>> | A SpaceState is a type of GameState that handles gameplay in a continuous
 two-dimensional space. | 
| SpaceThinker<T extends CellGame,U extends SpaceState<T,U,V>,V extends SpaceThinker<T,U,V>> | A SpaceThinker is the type of SubThinker that is used by SpaceStates. | 
| ThinkerObject<T extends CellGame,U extends SpaceState<T,U,V>,V extends SpaceThinker<T,U,V>> | A ThinkerObject is a MobileObject that mimics a type of SpaceThinker by
 permanently assigning to itself a SpaceThinker of that type. | 
| Viewport<T extends CellGame,U extends SpaceState<T,U,?>> | A Viewport represents a rectangular region of the screen through which the
 space of the SpaceState to which it is assigned can be viewed. | 
| Enum | Description | 
|---|---|
| CollisionResponse | A CollisionResponse is a possible response that a MobileObject can have
 to colliding with a solid surface. | 
| SpaceState.DrawMode | A DrawMode is a procedure by which a SpaceState determines the order
 in which to draw SpaceObjects with the same draw priority over one
 another. |