Anyone who has ever ran a simulation of the common space time diagram of gravity where planets appear on a elastic sheet knows that it is not an optimal representation of what is actually going on; the spheres on the sheet do not neatly revolve around eachother but rather quickly crash together.
What does the diagram really represent? In places of greater mass the sheet is lower, so the depth indicates gravitational force and gravity in turn warps space time. Volume around a dense object is pulled closer and becomes more compact, for a box to contain the same amount of volume while moving down the sheet it has to become relatively smaller.
Each circle travels past an equal area on both sides, in other words each circle is a straight line. This effect also explains why no object traveling at finite speed can return from the horizon of a black hole: it’d have to travel an infinite distance.
By filling three perpendicular planes with diodes emitting light invisible until three beams cross one can draw in the enclosed space by selectively turning on lights with a penremote, pemote!