Marble Sort Level 668 — Walkthrough and Solution

Marble Sort Level 668 is a board that looks open and friendly but hides a demanding order of operations. The key to success is recognizing that the early game is controlled by a pair of Connected Boxes sitting just behind the Dark Blue column on the left side. If you fail to clear that pair before moving on, the Conveyor Belt will jam and the level will become unwinnable.

The board is set up with a Top Tray that holds a pyramid of grey Hidden Boxes at its peak, and below that, two large 2x2 striped Tunnels dominate the center. The front row of the Top Tray has exposed clusters in this order from left to right: White, Light Green, White, Dark Blue, Light Blue, White, and Light Green. The bottom Boxes start with a front row of Light Green, Pink, Dark Blue, and White. Behind that Dark Blue sits the pair of Connected Boxes, also Dark Blue, which must be cleared early.

Marble Sort Level 668 Walkthrough

The bottom Boxes initially demand, from left to right: Light Green, Pink, Dark Blue, and White. The Light Blue cluster on the front lip is a decoy because there is no Light Blue bottom Box in the starting row. The Dark Blue column in the center, between the two Tunnels, is the critical path. You need to feed that column first to expose the Connected Boxes behind it.

The main trap is the Light Blue cluster. It sits exposed and looks like an easy tap, but it will occupy a Conveyor Belt slot that you cannot afford to waste. The early game is all about avoiding that decoy and focusing on Dark Blue, Light Green, White, and Pink to break through the Connected Box wall.

How to Beat Marble Sort Level 668 — Step-by-Step

Phase one: Breaking the Connected Box Pair

1. Tap the exposed Light Green cluster on the far left of the Top Tray's front lip, and route it into the first bottom Box.
2. Tap the exposed White cluster next to it, and deliver it to the fourth bottom Box.
3. Leave the Light Blue cluster alone.
4. Tap the Pink cluster inside the left Tunnel, and feed it to the second bottom Box.
5. Pull the Dark Blue clusters from the vertical stack in the center gap between the Tunnels, and drop them into the third bottom Box.
6. Once that front Dark Blue Box fills, the pair of Connected Dark Blue Boxes will slide forward. Immediately fill them with any remaining Dark Blue marbles you can find.

Phase two: Handling the Arrow Box Shift

1. After the Connected Boxes are gone, the bottom tray shifts and Arrow Boxes appear. These Arrow Boxes have black lines connecting them, and you can only fill a box that has no lines pointing to it.
2. Identify the root boxes, which have no incoming lines, and check their required colors.
3. Pull the exact colors demanded by those root boxes from the exposed layers of the Tunnels. The left Tunnel holds Yellow and Pink; the right Tunnel holds Dark Blue, White, and Orange.
4. Begin tapping the grey Hidden Boxes at the top of the pyramid, but only one at a time. After each tap, see if the revealed color matches an active Arrow Box. If it does not, leave it alone.
5. Clear the prerequisite boxes to unlock the tied ones. Prioritize filling any box that becomes unlocked to keep the tray moving.

Phase three: Clearing the Final Pyramid

1. Once the Arrow Boxes are mostly cleared, the remaining bottom Boxes will be standard, unlinked colors. Look at what you need to finish those columns.
2. Tap the remaining Hidden Boxes from the top down, one by one.
3. Watch the Conveyor Belt closely. Since Hidden Boxes reveal unknown colors, you are at the highest risk of a jam. If a Hidden Box reveals a color you don't need, search for a matching cluster elsewhere on the board to clear it quickly before tapping more Hidden Boxes.

Tips & tricks

• Always keep the Conveyor Belt as empty as possible. If you have more than two marbles waiting, stop and clear them before proceeding.
• Use the Tunnels as storage for colors you need later, but only if they are exposed and you can retrieve them without clogging the belt.
• When an Arrow Box becomes active, fill it immediately. Delaying can cause a chain reaction of blocked boxes.

Common mistakes

• Tapping the Light Blue cluster early is a classic error. It sits on the front lip, but there is no Light Blue bottom Box in the opening row, so it just wastes a belt slot.
• Ignoring the Connected Box pair and focusing on other colors first will cause a jam. You must clear that pair before the board opens up.
• Tapping two Hidden Boxes in a row without checking if the first color is usable can quickly fill the belt with unusable colors. Always tap one, check, and then decide.

Marble Sort Level 668 FAQ

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