Aha! Thank you for digging into this further.
Maybe the conceptual leap I’m having trouble with isn’t ‘specific vs universal’ variables, but understanding how to apply them.
Before, I was trying to use:
let the pen be a random colour
But then your example:
now the colour of item is a random colour;
What I think I’m starting to understand is that the ‘colour’ variable needs to be both ‘called’ and then ‘managed’ if that makes sense. My first attempt missed that step, just trying to say the ‘let the pen be a random colour.’
Not to mention the usage of ‘item’ to sort of ‘hold space’ for the pen while things are getting applied to it.
In the little bits of Javascript I’ve been learning, I could probably add a variable to itself or use it to modify the process in some way, but the natural language of Inform 7 obscures that point for me, if that makes sense.