Things have shape.
Shapes present our behavior with them.
It is called 'affordance'.
First, this thinking was used only psychology field.
But now, a lot of fields use it.
Those are industrial design, interaction design, artificial intelligence and etc.
There is a thing, which have a bulge.
We think that the bulge can push and something happen.
Also, There is a box.
We think that we can step the box or sit it.
Yesterday, I watched the video on the inter net.
Some people go out from their building.
They are pushing the glass part on the door.
But the glass was removed.
This video's people have put into the door-frame.
In this case, maybe they look only the door-frame.
And they think that Frame can keep glass.
And Glass sheet can push.
The video was very interesting.