Finland

Verdict:

Flag of Finland

The design of Finland is very similar to the other Nordic countries, featuring the Nordic Cross in blue with a white background

Keep It Simple. The flag should be so simple that a child can draw it from memory…
Use Meaningful Symbolism. The flag’s images, colors, or patterns should relate to what it symbolizes…
Use 2 or 3 Basic Colors. Limit the number of colors on the flag to three which contrast well and come from the standard color set…
No Lettering or Seals. Never use writing on any kind or an organization’s seal…
Be Distinctive or Be Related. Avoid duplicating other flags, but use similarities to show connections…

The simplicity of the flag cannot be denied. It is very well designed, and like the other Nordic Countries, anyone can draw it.
The blue is said to symbolize the blue sky and the white is said to stand for the snow in the wintertimes
As mentioned, the flag is related to all the other Nordic Countries in terms of shape and design, but is distinct enough to not cause confusion.