Difference between Isometric, Oblique and Orthographic Drawing

Isometric drawings involves dots and little details that results in extreme(ly) precise and accurate drawings. Isometric is 2d (2 dimensional).

Oblique drawings are different from isometric drawings in terms of dimensionals. Dots and geometry are greatly involved in it, just like isometric drawings.

Orthographic drawings are drawings which provides view from a 450 degree angle.

Sources: Oxford dictionary

Define the Theme - Environment

Environment refers to the surroundings of an object, regardless of wether it is a living or non-living thing.
It also refers to the aggregate of surroundings things.
Environment can be applied by many things like computer and ecology.
In the case of the computer, it means the hardware configuration and mode of operation.
In this instance of the ecology, environment means the a air, minerals, organisms...etc...

Source: en.wikipedia.org; dictionary.com