A second layer of ruby text only renders correctly (to the right) in some browsers, e.g. Chrome:
FirstMatrix
∘.×
SecondMatrix
So too, many browsers do not render tags (here, a line break) inside ruby text correctly:
FirstMatrix
+.×
inner
productSecondMatrix
Most browsers recognise the fallback syntax of ruby text:
Go to gaoljail now!
Here, the fallback is emulated with styling:
Go to gaoljail now!
And for Internet Explorer users, this is how the above line should have looked:
Go to gaol [American: jail] now!