These things must be a bitch to clean
(Limit 1 per customer. Subject to availability and export controls.
ACME regrets to inform its amiable clientele that a recent site visit to our manufacturer for the new Banach-Tarski Playkit has revealed that although the raw spheres have been delivered and are in-process, they are likely to remain on backorder for an unbounded amount of time.)
I've tried several times to make a Boys Surface. It's really hard to do. Bending tubing around its own radius - really challenging. Easy to kink, difficult to get uniform. I've commissioned my friend Lucas Clarke and he's had encouraging results; alas but I've seen too many shards of 30mm diameter borosilicate tubing.
Will keep trying...