Marble Sort Level 421 is a capital T, and the middle is the only part that matters at the start. The center column is packed with everything you need — yellow, red, green, dark blue and pink — running bottom to top. The two arms look tempting, but they're bait. Leave them until the front row changes.
The column runs yellow, red, green, green, dark blue, then pink. The left arm holds dark blue, orange, pink and yellow. The right arm holds red, orange and light blue. Down below you've got four columns of Boxes, and only the front row is safe to bank a color into at the start.
Marble Sort Level 421 Walkthrough
The front row opens with a pink-red Box on the far left, two yellow Boxes in the middle, and a green Box on the far right. Behind them sit green, dark blue and pink. That front row is your one safe target while the column is still plugged, so read it before every tap.
Everything hangs on the yellow block at the base of the column. It's the plug. Clear it and the column starts moving. Grab an arm instead and the marble drops onto your Conveyor Belt with no Box to land in — it just loops there and eats a slot.
How to Beat Marble Sort Level 421 — Step-by-Step
Break the center plug
- Tap the yellow block at the base of the column. Send it into the two yellow Boxes sitting in the front row.
- Tap the red group above it. Route it into the pink-red Box on the far left.
- Clear the two green groups. The first feeds the green Box on the far right, the second feeds the green Box behind it.
- Leave the side stacks alone. The dark blue on the left and the red on the right have no Box yet, so they'd just loop.
- Tap the dark blue. It drops into the dark blue Box that slides forward in the third column.
- Finish with the pink group at the top.
Clear the side stacks
Once the column is empty, the front row shifts to dark blue, orange and lighter pink. That's your signal that the arms are safe to touch.
- Pull the dark blue group off the top of the left arm into its fresh Box.
- Wait for the orange Boxes to slide into the front row, then take orange from both sides.
- Hold the red on the right until a matching Box shows up on the left. Grab it early and it clogs the belt.
- Drop both orange groups to clear the middle of each arm.
Finish the last box shift
What's left is light blue on the right and a pink-and-yellow mix on the left. This part goes wrong when you rush.
- Keep at least three empty slots on the Conveyor Belt.
- Release the light blue on the right — a light blue Box slides up in the left column.
- Drop the last pink and yellow from the left arm.
- Only tap a corner when the matching Box is actually visible in the front row.
Tips & tricks
- Read the column bottom-to-top before your first tap: yellow, red, green, green, dark blue, pink.
- Treat the front row as your only safe target. If a color has no Box in that row, leave it where it is.
- Watch the third column — the dark blue Box shows up there after you clear the green groups.
Common mistakes
- Pulling dark blue or orange off an arm in the opening. Neither has a Box yet, so the marble loops on the belt.
- Emptying a top corner in the endgame just because it's clickable. Only release when the matching Box is in the front row.
Marble Sort Level 421 FAQ
Why does my Conveyor Belt flood on Marble Sort Level 421?
You grabbed a marble off one of the arms before a matching Box existed. Only the center-column colors have Boxes in the front row at the start, so anything from the sides loops on the belt. Break the center plug first.
Which color do I clear first on Marble Sort Level 421?
The yellow block at the base of the center column. It's the plug holding the whole T together, so clearing it unlocks the column above it. Feed it into the two yellow Boxes in the front row.
How many moves does it take to clear Marble Sort Level 421?
Roughly a dozen taps across three phases — break the plug, clear the side stacks, then juggle the last light blue, pink and yellow. Follow that order and nothing gets stranded.
Do I need boosters to beat Marble Sort Level 421?
No. Clear the center column bottom-to-top and the level unlocks itself. Save your boosters for boards with hidden Boxes or locks.
What happens if I pull from the side arms too early?
The marble drops onto the Conveyor Belt with no Box to land in, so it loops and takes up a slot. One early grab can stall the run before the board shifts.
Get the Official Game
Back to the full Marble Sort level list.