Knot in 3D is a ZX Spectrum action game by Malcolm Evans published in 1983 by New Generation Software.

It resembles a three-dimensional (i.e. with three degrees of freedom instead of only two) version of the Light cycles game from the film Tron.

The game takes place in a 16 × 16 × 16 three-dimensional grid with the display being a first-person view of what the player can see in front of them.

Initially empty, this space is filled up by the player (who constantly moves forward) leaving a trail behind them.

[2] In 1997, Next Generation reflected on Knot in 3D as "a landmark title blighted by the inability of most players to think in terms of three dimensions fast enough.