Exerting pressure - the girder

The distribution of pressure is visualized by light. In the long rectangular piece the pressure is contracted particularly at the point where you are pressing your finger. If the pressure were to increase, that would be the place where the object would break. In strutted material the pressure is distributed evenly: colour can be seen everywhere. Due to the manner of construction, the pressure is spread across many points. That is why the grider can bear much greater pressure before it breaks.