Slider

Slider
ZZT-OOP name	sliderns
Internal ID	25 (0x19)
Character	#char 18 ↕ (0x12)
Category	terrain
Stats?	no
Other traits
Effect on movement	pushable (north and south)
Destructible?	no
Uses ZZT-OOP color names?	yes

Slider
ZZT-OOP name	sliderew
Internal ID	26 (0x1A)
Character	#char 29 ↔ (0x1D)
Category	terrain
Stats?	no
Other traits
Effect on movement	pushable (east and west)
Destructible?	no
Uses ZZT-OOP color names?	yes

Sliders are a pushable terrain elements that come in two varieties: the sliderns which can only be pushed north and south, and the sliderew which can only be pushed east and west.

Sliders, along with boulders and pushers, are essential elements of "slider puzzles". However, they cannot be pulled by the player, meaning that it is easy for sliders to become stuck in a corner or against a wall. Sliders cannot be destroyed by the player, so a stuck slider in a game can often lead to a softlock.

Sliders keep their background color when they move, although this is not noticeable unless STK colors are in use. This behavior disappears if the slider is given stats.

Erasure of fake walls

Just like boulders, sliders leave empties behind them when they are moved. This can be an issue for games that use fake walls as floors, as pushing a slider across a colorful floor will erase a black trail across the floor. This erasing behavior happens because sliders lack stats by default, and thus lack a way to track their under tile. Other statless pushables (ammo, gems, keys, and boulders) also exhibit this erasing behavior, though it is most noticeable with boulders because boulders are more easily manipulated into areas of a board that have fake walls.

This erasing behavior can be eliminated by giving the slider stats, though the number of sliders that can be treated this way is limited by the board's stat limit.