Fill an object with parallel lines that are equidistant from each other

My goal with my previous question is to fill up the dragon Spryo. The horn should be in triangles like this, the wings should follow the pattern of the spacers.How do I create those corners?

I work with windows. How do you rotate the elements. You explained in your previous post, but I'm not fully following.

Thank you very much!

You can use Pattern fills and use an additional color fill below them with the Appearance panel.

Curved lines can be clipped with a Clipping Mask.

A script that cuts paths may help too, see:

https://github.com/creold/illustrator-scripts/blob/master/md/Path.md

As an example: Make a pattern swatch that consists of a rectangle the same colour as the strokes you ultimately want to use in your drawing, and a no stroke/fill rectangle. Drag them (as one) to the swatches panel:

Draw your face (or whatever). In this example I made it a live paint group after completing the linework, added the base colours, then expanded the live paint group:

Then you can add the pattern swatch as a second fill on those shapes that require it, and rotate the fill as needed (in the transform panel, select 'transform pattern only', or hold the ~ or ¬ keys --depending on your system while using the rotate tool).

So it's not just straight lines that I want to use. I also want to have curved lines like you can see in the image of the artist on the neck and chest.