Truncating a cube once yields an Archimedean solid with six octagonal faces, and eight triangular faces, all regular. A second truncation can be made to produce the solid shown above. It also has, as faces, six regular octagons and eight equilateral triangles — and, in addition, twenty-four isosceles triangles.

I made this using Stella 4d, software you can try for yourself at www.software3d.com/Stella.php.