I have no real information about this effect. It works and it easy to do.
There is no forcing, but you do use up 2 envelopes each time you perform it. The coins can’t be examined and I’m not sure how convincing it is with the envelopes.
I think if I wanted to perform this I would use a 4 way wallet and the Miller Miracle Wallet would be perfect. This would make the effect more convincing, instantly repeatable, and you would not need to keep making up envelopes. Also I would replace the coins so that they could be examined.
But frankly I’m not sure the effect is worth the effort, so I’m leaving it as is 🙁
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