Only 6 of these 12 signs are correct: find the errors in 6 of these signs!
b) the inside color should be blue and not grey;
f) the double curve is drawn in a different way;
h) the little rocks thrown by the wheels are missing;
i) this sign should be in the shape of a trangle;
m) this sign should be blue, not green;
n) the bike colour should be black, not red.