Safe snacks

I just can't read a story about "hardness indicators" without laughing. Apparently, there is a new system for letting customers know whether the rice cracker they are about to bite into is really a rock or if they can eat it without putting in their dentures. According to the Mainichi newspaper:
"Rice cracker fans' teeth may get a break from April when the popular snacks will come out with clear indications of their hardness, preventing accidents from biting a biscuit that's too hard."
The photo shows what the labels will look like. The far left is the softest; the far right, the hardest. Is it just a coincidence that hard harder the cracker gets, the larger the indicator gets as well?