Useful Material Or Knowledge Crossword Clue 5 2 3 4

I think this clue might be broken. But if forced: — that’s 4,3,6 — no.

Crossword puzzles are the ultimate test of vocabulary, lateral thinking, and pattern recognition. But every so often, a clue appears that stops you dead in your tracks. One such challenging clue is: followed by the letter pattern (5,2,3,4) . useful material or knowledge crossword clue 5 2 3 4

What 2-letter word? TO , IN , OF , BY .