Elevation  obliques are a form of   axonometric drawing. You can see three sides, and it is all to scale on each plane.

The elevation sits at the front, and lines are projected at 45 degrees off to one side. All the components are to scale - which looks weird, but is accurate.

Often the oblique part is drawn at half the real scale, which looks more like a perspective and is easier to read.

The lines can be also projected at 30 degrees, which also looks more like a perspective.

To draw an elevation oblique place the plan at 45 degrees - project the lines up. Find the heights from an elevation

add the walls and window - all to scale.

A lot of drawing programmes will use this form for a cube. Add a few cubes together to create an elevation oblique

Traditionally this view is used to draw a cube.