About Bolt Sort
Bolt Sort is a workbench puzzle. A row of threaded bolts stands on little wooden bases, and each bolt holds up to four colored hex nuts. The nuts start out jumbled, and you win by moving them until every bolt carries four nuts of one color, or nothing at all.
We drew everything in the browser, down to the thread lines on the bolts, and we gave the nuts a proper spin: as a nut travels up or down a thread it rotates, so lifting a stack really looks like unscrewing it. When a bolt is finished it gets a little colored cap and a burst of confetti.
Every level comes from its level number, so the same level always has the same layout, and each one is checked by a solver before it reaches you. We ran the first 200 levels through our solver and a second, independent one, and all of them are solvable. If you like this kind of puzzle in 3D, Screw Creek is our screw-sorting puzzle app for iPhone and Android.
How the levels change
Levels 1 to 3 use three colors, and one new color is added every three levels up to ten colors from level 22 on. There are always two more bolts than colors. We also rotate between three starting layouts so the game doesn’t feel like the same puzzle with more paint:
| Layout | When it appears | What it looks like |
|---|---|---|
| Stacked | Levels 1-2, then most even levels | Every colored bolt is full, two bolts start empty |
| Scattered | Most odd levels from 3 | Nuts are dropped at random, so bolt heights vary |
| Tight | Every third level from 18 | Four bolts hold three nuts each and only one bolt is empty |
Tight levels are the hardest. With only one empty bolt, the free spaces are spread thin and one careless move can box you in.
How to play
- Tap a bolt to lift its top nut. Any nuts of the same color directly beneath it lift with it as a group.
- Tap another bolt to screw the group on. That works when the target bolt is empty, or when its top nut matches the lifted color and it has room.
- As many nuts as fit will move. If you lift three red nuts and the target has one free spot, one nut moves and the other two drop back down.
- Tap the same bolt again to put the nuts back. Tap a bolt that doesn’t match and it shakes, and that bolt becomes your new selection.
- Fill every bolt with four nuts of one color to clear the level.
Your progress, the highest level you’ve reached, and your symbol setting are saved in your browser. There is no timer.
Helpers
You get three undos per level, and each undo counts as a move. Once per level you can add an extra empty bolt, which stays for the rest of the level. Restart resets the board and refills both helpers. If the game detects that your current position can no longer be solved, a “Jammed!” screen appears, tells you whether an extra bolt would help, and offers Undo, Add bolt, or Play again.
The Symbols button prints a shape on every nut (circle, star, heart, and so on), one shape per color, for anyone who finds some colors hard to tell apart.
Strategy tips
1. Look for the free spaces first
Every level has exactly eight free slots across all bolts at the start. On stacked levels they’re two empty bolts. On scattered levels they’re spread around. Know where your space is before you move anything.
2. Move whole groups when you can
Because matching nuts travel together, moving a group of three reds onto a red is one move instead of three. Setting up a big group and then moving it is usually better than chipping away one nut at a time.
3. Don’t split a group unless you mean to
If the target has less room than your group, some nuts get left behind. Sometimes that’s exactly what you want, but often it leaves two half-groups that each need a home.
4. Finish the easy color, then use its bolt
When a color has three nuts near the top of different bolts, gather it first. Each finished bolt removes clutter, and the bolt you emptied along the way becomes new working space.
5. On tight levels, keep the empty bolt empty as long as you can
With only one empty bolt, it’s your only flexible spot. Try to make matching moves first and only use the empty bolt when it lets you uncover a color you can finish right away.
6. Use the extra bolt when you’re stuck, not before
The extra bolt is strongest late in a level, when one color is trapped under another. Early on it mostly gives you room to make a bigger mess.
FAQ
Is every level solvable?
Yes. Each layout is checked by a solver before you see it. If a layout can’t be solved quickly, the game picks a different one for that level number.
Why did only some of my nuts move?
A bolt holds four nuts. If the target has fewer free spots than your group, only that many nuts move and the rest settle back on the original bolt.
Does using undo or the extra bolt affect anything?
No. The level counts as cleared either way. The win screen simply mentions when you finished without using undo.
Can I go back to earlier levels?
Yes. After a win, Play again replays that level, and the start screen has a button to jump to level 1 without losing your saved progress.
