Half of the American state flags are like that. A seal plus a blue background. Boring, unimaginative, seriously lacking any cultural significance, deprived of any creativity, and just plain repetitive and idiotic. At least Delaware uses light blue, Nevada puts their seal in the corner, Alaska doesn't use a seal, and Washington state uses green.
Best flags: Hawaii, Alaska, Maryland, New Mexico, Ohio, California, Colorado, Georgia, and any other flag that doesn't use the same pattern
For the somewhat-grammatically-challenged, could you provide some examples of ordinal and adverbial numbers? In particular, how they differ from cardinal numbers?
I think I could have understood your explanation a few years ago, but at the moment they're all just numbers to me. o.O
There are no grammatical endings in unu and du and the fact that their last letters happen to be the same (as each other and as the ending of imperative mood) is just accidental.
Other numerals are tri, kvar, kvin, ses, sep, ok, naŭ (3–9), nul (0), dek (10), cent (100) and mil (1000).
None of the languages which Zamenhof knew and upon which he based Esperanto has any regular grammatical ending nor deeper structure regarding numerals. Notice that using any fixed grammatical ending would require making the numerals twice as long (two syllables instead of one) or distort heavily their sound (now recognisably cognating with Latin and its descendant languages).
Not quite. You're right that nominal predicates (e.g. with the verb esti) are constructed in Esperanto with the nominative case (without the -n ending).
However, in this case, that's not the literal meaning of your sentence in English. You don't want to say that “the flag is a colour”, so the literal translation (using esti) won't work this way.
You have either to go back and use the verb havi or reanalyse the English usage of “one colour” not as a noun phrase, but as a adjectival phrase (so as a description, as in “That's a one colour flag.”), and thus say La blua flago estas unukolora (without the -n ending, as you've wanted).
So, there are three different things.
The word unu is a numeral meaning “one”. The third-person indefinite pronoun “one” (like in English “One does not simply walk into Mordor.”) is in Esperanto oni. There’s also the word on·o (“fraction”), which is a noun created with the suffix -on- like in the words du·on·o (“half”) or kvar·on·hor·o (“quarter-hour, 15 minutes”).