What do the round 5 and 3 units mean?

They are completion-driven stages; completed receiver groups reduce their values until they convert into top trays.

Which receiver should be established first?

The right inner tray clears early and becomes the first large purple receiver.

The long green drain exposes upper-right pink and green; top-left orange, purple, and lower-right cyan then finish before `0/16`.

Car Sort level guide

expert 7 colors

Car Sort Level 526 packs layered top and lower towers around a sixteen-space loop controlled by two completion-driven cylinders marked 5 and 3.

If the player asks you to sign in, open the video on YouTube instead.

Dispatch exposed cyan and orange, then route the first green and purple cars from the layered towers.
Empty the right inner vertical tray and establish the large purple receiver.
Advance the lower-left tower into green and the lower-right tower into cyan one hidden row at a time.
At `16/16`, wait for a receiver to drain before exposing another patterned row.
Complete early green, purple, and yellow groups to reduce the top cylinders from `5/3` to `4/2`.
Build green in the left inner tray and orange in the center tray while the long horizontal tray transitions into a green receiver.
Route red into the cleared left receiver and keep purple feeding the right receiver.
Advance the remaining cylinder stages until the upper-right tray reveals its late pink and green groups.
Drain the long green traffic, complete upper-right pink and green, then finish top-left orange, purple, and lower-right cyan in that order.
Confirm the last cyan group clears the road to `0/16` and triggers the `Smooth!` completion feedback.

Colors in this level:

Cyan, Orange, Green, Purple, Yellow, Red, Pink

Board notes 5 details

Layout: Two layered top columns, a long horizontal shutter tray, three inner vertical trays, and two lower hidden towers share one compact rectangular loop.
Goal: Clear the lower towers, build the large inner receivers, reduce the round `5/3` stages through completions, and finish the new top trays they reveal.
Opening: Dispatch cyan and orange first, then route exposed green and purple so the right inner tray can become the first large purple receiver.
Danger Zone: Occupancy reaches `16/16` before the first receiver drains; opening another patterned row then can lock every remaining color on the loop.
Mechanics: Hidden car-icon rows combine with round completion gates that fall from `5/3` to `4/2` before converting into ordinary top trays.

What do the round 5 and 3 units mean?
They are completion-driven stages; completed receiver groups reduce their values until they convert into top trays.
Which receiver should be established first?
The right inner tray clears early and becomes the first large purple receiver.
Which colors close the late reveal sequence?
The long green drain exposes upper-right pink and green; top-left orange, purple, and lower-right cyan then finish before `0/16`.