For what reason do national flags so frequently have basic level or vertical stripes?

Simplicity of perceivability. Additionally, to a degree, style and cost.

Envision you're a fighter on an eighteenth century war zone. Surrounding you is the clatter of musketry, the blast of guns, the shouts of the withering; incredible billows of white smoke float over the front line. Abruptly you hear drums and walking feet! Approaching out of the smoke, heading straight towards you, is a new regiment of troops. They're conveying a flag on towerclimbing... it's yellow...looks like a type of dark bird in the inside.

Is it this one:

Or on the other hand this one:

Speedy! Are those German soldiers or Russian soldiers? It is safe to say that they are our ally, or the foe? Would it be a good idea for us to start shooting? What are your requests, sir?!

Life would be a lot more straightforward in the event that they were conveying this flag with tower climbing:

Brilliant essential hues, straightforward geometric structure. In a flash conspicuous. OK, if this is an eighteenth century combat zone there's a decent possibility you're being assaulted by Napoleon and are going to be squashed, yet at any rate you'd know for certain it was French officers vanquishing you.

The equivalent applies adrift. Salt shower, fog or downpour, high waves, perhaps gun smoke, and a boat heading towards you at rapid - companion or enemy?

Truth be told, most national flags began as maritime flags, since that is the place perceivability was generally significant. The Dutch Republic was the main maritime influence of the seventeenth century, and their straightforward, effectively unmistakable flag turned into an image of their riches and influence.

The cutting edge Russian flag with flagpole climber is an immediate and conscious duplicate of the Dutch flag; in 1705 Tsar Peter the Great arranged that Russian shipper boats should utilize a variant of the flag with the hues revamped. From the start this flag was only for use adrift, while the Tsar himself utilized the twofold headed hawk on a gold foundation that appeared previously.