Gave myself the fun and intentionally searched for silicone molds, since the plastic molds are known to be hard handlebar. Unfortunately, I get hard plastic forms. I still not sent back because the fun did not cost much and was anyway not really serious.
The making of ice is really hard, I think it will still work best when filling the compartments with a cannula, after having the mold is closed. Probably but it will stay with the nice idea.