How to tell similar flags apart
A handful of flag look-alikes account for most of the mistakes in the flag quiz. None of them are actually identical — each has one small, reliable tell.
Romania vs Chad
Both are plain vertical blue-yellow-red tricolors, and the two shades are close enough that most players simply guess. There's no visual trick that works reliably — this pair is memorized by repetition rather than spotted at a glance.
Indonesia vs Monaco
Both are a plain horizontal red-over-white bicolor. The only real difference is the aspect ratio: Indonesia's flag is wider and shorter, Monaco's is closer to square. In practice this one is also mostly memorized rather than read off the shape.
The Nordic cross countries
Denmark, Sweden, Finland, Norway, and Iceland all use the same off-center cross design, so the fast way to separate them is color: Denmark is red-and-white, Sweden is blue-and-yellow, Finland is blue-on-white, and Norway and Iceland both mix red, white, and blue — Norway's cross is thinner and set closer to the edge, Iceland's is set further from the edge with visibly thicker white borders.
Ireland vs Côte d'Ivoire
Both are vertical tricolors using green, white, and orange — but in reverse order. Ireland goes green-white-orange from the pole side; Côte d'Ivoire goes orange-white-green. If you remember that Ireland's green comes first, the other one follows by elimination.
Chad vs Romania (again) and Moldova
Moldova uses the same blue-yellow-red bands as Romania and Chad but adds a coat of arms in the center, which is the one detail that instantly rules it out from the other two.
Australia vs New Zealand
Both use a dark blue field with the Union Jack in the corner and stars on the right. Australia has the large seven-pointed Commonwealth Star below the Union Jack plus a five-star Southern Cross; New Zealand skips the Commonwealth Star and uses only four red-and-white stars for its Southern Cross.