In the nucleus of the atoms of the elements concerned
I believe the principle of design you are referring to is Balance. This is because the concept of balance is supposed to create a visual equilibrium and it's mainly because our eyes and mind are always trying to focus and create a sense of symmetry and coherence. The reason is because our minds want to work out some stability.
Refer to the related links for more information about 5 elements that are an exception to the Aufbau principle.
The master sergeant serves as the principle NCO in staff elements at battalion or high levels.
how describe art elements
elements of mind
A firm's distribution strategy is concerned with two key elements: