I think he used like a bunch of these or similar? Not sure because he described it over the phone. That's what I would use.
You can buy unfinished hexagon wood cut outs from craft stores or Amazon. [Like these here. ](unfinished hexagon wood cutouts for crafts (4 x 4 in, 15 pack) https://smile.amazon.com/dp/B093KGXK1K/ref=cm_sw_r_apan_glt_fabc_HRTTHT851D863Y0GP4JA)