I made this former to construct a wobble board (also pictured) for the grandchildren. The idea is to laminate layers of thin ply and bend them to shape on the former. The holes are for the clamps that hold the ply in place. There are videos on Youtube which describe the technique (see link below) but I can explain in more detail to you face to face if that helps. Half the job is making the former. This worked well and I was very pleased with the outcome; so were the grandchildren! Just to be clear, I am offering the former but not the wobble board that I made using it (sorry).

https://www.google.com/search?q=diy+wobble+board&rlz=1C1CHBF_en-GBGB803GB80...

DIY wobble board former (East Hendred OX12)