About the categories
Feasible inventions: It just means that, in my view, to turn ideas in this category into commercial offerings is a do-able task. I’m fully aware of the effort required, even for really high quality ideas and I’m not saying anything about profitability.
Possible inventions: With a fair wind and some suspension of disbelief it might be possible for ideas in this category to get to market.
Whimsical inventions: Not capable of ever becoming a real deliverable, but still perhaps of value in suggesting other avenues of thinking -or just mad.