Locked glass is the first special kind of glass in PaneSlide. It appears on its own at level 12, with a small ✨ tip, and then comes back regularly in later chapters. It looks like any other pane, with a padlock in the middle, and it cannot be moved at all.
What locked glass does
- It never moves. Swiping it does nothing, and it does not use up a move. It is already in its final position, so it is part of the answer from the start.
- It still blocks its own rail. Like any pane, locked glass has a direction. Panes on the same kind of rail cannot overlap it, so they stop just before it, exactly as they would stop before any other same-rail pane.
- Crossing glass sticks on it. Because sliding onto new colour makes a pane stick, a crossing pane that slides onto locked glass stops right on top of it, showing the mixed colour.
- It mixes colours normally. Its colour counts in the picture like any other glass.
In short, locked glass is a stopper you can rely on. It will be in exactly the same place on every swipe.
Why it makes puzzles easier to read
Fewer moving parts means fewer possibilities. A board with one locked pane has one less pane to think about, and the locked pane also tells you precisely where some other panes must stop. That is why level 12 has a slightly lower par than the levels around it: it is a "teach" level, designed so the new idea is the only new thing to learn.
How to use locked glass
Count it out of par
Since locked glass never moves, it is never part of the solution's swipes. When you count how many panes are out of place, skip it.
Look for panes that will stick on it
Trace the rails that cross the locked pane. Any crossing pane that slides across it will stop on it. If the picture shows a mixed colour on top of the locked pane, that is a big hint: a crossing pane needs to end there, and one swipe in the right direction will put it there.
Use it as a wall for its own rail
If a pane on the same kind of rail needs to stop next to the locked pane, just swipe it towards the locked glass. It will glide and stop in the neighbouring cell. This is often the simplest swipe on the board.
Remember it can be in the way
Locked glass can also be a problem. A pane that needs to get past it on the same rail never can, so it must reach its target from the other side. If a crossing pane needs to pass over the locked pane without stopping, it can't, because it will always stick there first. That limits which direction you can swipe it from.
Tip. On a board with locked glass, start by looking at every rail that passes through the locked cell. Those panes' moves are decided by the lock, and they are often the first or last swipes of the solution.
Where locked glass appears
After level 12 it returns throughout Levels mode. PaneSlide's chapters are 20 levels long. Each chapter features a couple of the special kinds more often and brings every other kind you have learned back at least once, so you never forget how one works. A level never mixes more than two special kinds (three only on rare challenge levels after level 100).
Locked glass vs stone pillars
From level 25 you will meet stone pillars. Both never move, but they behave differently:
| Locked glass | Stone pillar | |
|---|---|---|
| Has a colour | yes | no |
| Same-rail panes | stop before it | stop before it |
| Crossing panes | stick on top of it | stop before it |
| In the picture | shows its colour | shows grey stone |
So a pillar blocks everything, while locked glass only blocks one rail and acts as a sticking point for the other. Knowing that difference is the key to the mixed boards in later chapters.
Ready to try? Open the level map and play from level 12, or read about the other glass in the guides.
Locked glass is also the star of the first boss, at level 20. See Sunroom and Greenhouse tips and boss levels.