Green pin / stationery

On the average,
when you drops a pushpin to the floor,
it hurts somebody's foot.
so, that is behavior of warning to drop pushpins.
But "Green pin" is different.
when you miss a pushpin while you are unconscious,
it doesn't matter.
Because a part of keen at pushpin always go down.
you can step on it as like lawn.
and also when you put it in the wall, you can plants sprout.