Just a minor thing, The diagonals in your stop sign are 5 blocks, And the straights are 4. Due to the fact that a block is longer from corner to corner then from one face, The diagonals are actually about 7 blocks in true length, Where the straights are still only 4. This makes the stop sign not really look like an octagon.
I'd suggest a pattern of 6, Then a 2 diagonal, Then six in another direction, Leaving a 4 diagonal from the last block of a straight to the first block of the next straight. Which will probably look better.