[notreallythough]

It's a series of tools and components required to fit certain related theories?

In carpentry you have many standardized off-the-shelf tools and components (hammers, nails, windows, tiles, dimensional lumber) and you have an almost endless number of ways to combine them. You can also create your own tools and components (which is harder). You also have some pre-determined guidelines that are meant to protect/regulate things so that they're safer and easier for a wider audience to live with, maintain, and edit (building codes).

Any of this stuff will work together as long as you stick to the constraints of individual objects as they fit into the laws of physics (a component can only bear X load in Y configuration).

The concept of "properly" is a bit varied. I can build a house with mud and straw and it's a "proper" house in some parts of the world... but it might kill me in an earthquake. This might be due to a pre-determined assessment of earthquake risk, or it might be because of limited knowledge and resources available (very common in coding, and often OK in small scale scenarios).