designed in blender and retouched in gimp to make good brightness then in inkscape and text added and highlight

Wow blaz_boy, you do awesome work!
I haven't replied to all of the images you've shared here, but have been impressed by every single one.

Can I ask how you did this one, and the triskel ("what is that called" topic)? How did you make them look....thick....or tall...or 3d? Did you do that by hand, or is there a tool in Blender you used? I don't have Blender, so I don't know what tools it has. (It's like the toys of a small child, you know the ones I mean, very simple puzzles made out of some soft, thick, squishy kind of material?) I love that effect, where a flat image is kind of stretched upwards to become 3d. It may not be within my current skills and abilities to do it, but I would be very interested to know if you did it all by hand, or if a particular graphics tool was used. If you don't mind sharing?

well , it's very easy thing
1- draw the object in inkscape and save it SVG (here was that eagle)
2- open blender and select the file>import > paths (ai,svg...etc) to import your svg file
3- the path is imported so enable the extrude by the value u want
4- render it and save the image
5- open inkscape and trace the image but make it look beautiful and choose a good colors
6- add some effects and text and your signature
DONE

yeah , that's right but the extrude of inkscape doesn't make it with a professional way
the extrude of blender manage the perspective and make it in the right way
if u extrude the shape in inkscape it just copy the shape and move it with distance and draw lines in the edges