Marble Sort Level 12 Walkthrough: Blue Box Bait

Level 12 Board Overview: Three Blue Boxes, One Blue Block

Level 12 lies to you on the loading screen. The bottom of the board is a wall of Blue Boxes, and the Top Tray offers exactly one Blue block you can actually reach. Everything else is buried. Purple, Orange, Black, Green, Blue, and Pink are stacked in a jagged grid, and a Tunnel showing a countdown of 3 is tucked into a cutout on the right edge, hoarding marbles you will need later.

The tray’s bottom row reads Black, Pink, Green, Blue from left to right, with Green, Black, Purple, and a second Blue directly behind them. The top-left corner of the board is missing entirely, leaving a jutting chunk of Orange and Purple that matters only at the very end.

This level is a space-management exam. Your Conveyor Belt is the lifeline, and the board is designed to fill it.

The Trap in Marble Sort Level 12

• The Blue wall is short one supplier. The front Boxes want Blue in columns 1, 3, and 4 (plus Black in column 2). The tray gives you one immediate Blue. The second Blue hides in the row behind — you have to dig for it.
• Pink and Green block everything. They sit in the front row of the tray with no matching Boxes open. They must move to unlock the board, but every one you drop parks on the belt.
• The left side of the belt is the graveyard. Dump Pink early and carelessly, and column space on the left clogs before the Tunnel ever opens.
• The Tunnel timing is forced on you. The right side of the tray cannot fully clear without triggering it, so you do not get to choose whether — only when.

Marble Sort Level 12 Step-by-Step Walkthrough

Keep the belt lean. Only drop what has a home, plus the two sacrifices this board demands.

Opening: make room with Black and Blue

1. Tap the bottom-left Black marbles into the Black Box in column 2. It clears instantly and reveals another Blue Box behind it.
2. You are now staring at four Blue Boxes across the front.
3. Tap the bottom-right Blue block to feed one of them.
4. Pink and Green still block the tray with no Boxes open. Bite the bullet: tap both onto the belt as deliberate sacrifices.
5. The second row of the tray is exposed. Take the Black marbles from it — feed them if a Black Box has stepped up, otherwise hold them on the belt.
6. Drop the second-row Blue marbles into another front Blue Box.

Mid-game: spring the Tunnel, hold your nerve

Clearing the right side of the tray finally activates the Tunnel.

7. The Tunnel drops a set of Pink marbles into play — exactly what the board needs. The second Box layer has surfaced by now, with Pink, Green, and Orange Boxes moving to the front.
8. Send the Tunnel’s Pink marbles straight into the Pink Box that appears in column 1.
9. Your belt looks awful right now — leftover Blue and Green parked right, maybe stray Pink left. Do not panic and do not dump.
10. Tap the exposed Green marbles into the Green Boxes in columns 3 and 4.
11. Those clears drag the whole right side of the lower board forward and expose a critical Black Box in column 4.

Cleanup: the Orange-Purple stack

12. The deepest Box layers flip to the front — Purple and Orange now run the show.
13. Drop the Orange marbles from the top-left chunk of the tray into the Orange Box in column 2.
14. The Boxes left in columns 1, 3, and 4 are all Purple. Tap the remaining Purple marbles from the top and middle of the tray to fill them.
15. Flush the last Black set into the final Black Box in column 4 and watch the board empty.

Level 12 Tips Recap

• Count Blue suppliers against Blue Boxes before you start — the missing one is behind Pink and Green, so the sacrifices are not optional.
• The Tunnel’s Pink payload is a gift, not a hazard. Have column 1’s Pink Box ready for it.
• An ugly belt is fine as long as every parked marble has a Box coming. Panic-tapping is what actually kills the run.