The parent comment that a coin of lead and balsa wouldn't be biased, but to clarify, the linked research paper states it can't be biased unless allowed to bounc

The parent comment that a coin of lead and balsa wouldn't be biased, but to clarify, the linked research paper states it can't be biased unless allowed to bounce/spin. Maybe your weighted cylinder flipping is not biased if you throw+grab instead of letting it land?