Drag the pieces back into a painted landscape. Three rounds — 3x3, 4x4, 5x5 — against the clock.
Six pieces wait in the tray under the board. Drag one onto the spot where it belongs; when it lands close enough it snaps into place and the next piece comes up.
A piece only locks at its own spot. Drop it anywhere else and it simply slides back to the tray — nothing is lost but a moment.
The board shows a very dim version of the finished picture. Use it to work out roughly where a piece goes, then let the ridge lines, trees and reflections tell you exactly which slot.
The clock starts when you first pick up a piece and runs across all three rounds. Finishing the 5x5 stops it. Lower time is better.
Corners and edges first is the oldest jigsaw advice, but here you cannot hunt for them: the tray shows only six pieces at a time, drawn from a shuffled queue, and a new one rises only when you place one. Work with what you are given instead. Flat sides still help — a piece with two flat sides is a corner, and one with a single flat side lies on the border — so when one of those comes up you already know most of where it goes and can place it at once.
After that, sort by the sky. Every picture here is painted with a strong top-to-bottom gradient, so the colour of a piece tells you its row almost on its own: a pale warm piece belongs near the sun, a near-black one near the waterline. Getting the row right leaves you only a handful of columns to test.
The columns are what the details are for. A ridge line crossing a piece at a particular angle, a tree clipped at the edge, one of the bright reflection strokes on the water — none of these is unique on its own (every picture has fifteen trees, nine reflection strokes under the sun and five birds), but where a detail enters and leaves the piece, and how much of it the piece carries, usually is: check it against the dim picture on the board. The sun and the boat appear only once, so pieces carrying them are placeable immediately. The pieces that cost you time are the ones from open sky, and those are worth leaving until last because by then only a few slots remain.
The rounds get bigger, not harder, and time carries across all three. That means the 3x3 is where a good run is won or lost in percentage terms: it is over in seconds, so hesitating there costs proportionally far more than hesitating on the 5x5. Move fast while the board is small.