Hi John, thank you for your note. The question you asked is one of the reasons that made me write this post. :)
The reason why I split up the white dot into 3 is to illustrate the effect of knowing 1 out of 3 (because it’s “3”/4).

aren’t the results of all 4 dots fixed/known?

No, not fixed. The amount of information is reciprocal of the probability. I fixed them artificially to show you why it’s reciprocal.

Popping 4 bubbles (when the odd is 1/4) is also just an illustration of taking reciprocal. When the odd is 3/4, if you take the reciprocal, the amount of information becomes 1.333, not 4.