If chairs could talk...
I know it's random. But if I was a chair (krzeslo) and I said "I was" would I say "bylem" or "bylam"?
That's not that random, from the grammar point of view. The answer is... neither. Look here, czas przeszły (past tense), n for nijaki (neuter). The first person singular is "byłom". Or rather 'would be' - as you see, it's written with a grey font. This denotes 'a potential or rare form'.
Neither. Byłom ! This is purely theoretical. I remember that Jacek Dukaj in his book Perfekcyjna niedoskonałość. Pierwsza tercja Progresu (which can be roughly translated as: Perfect Imperfection, First third of Progress) added new type of being, personalized artificial intelligence. It constituted new type of gender, the fourth one with completely new conjugation. This made book hard to read for me, so unusual. Examples : „nu weszłu” (?it? came in), „przyszłu” (?it? came), „zobaczyłu” (?it? saw), „uścisnął jenu dłoń” (he grabbed ?its? hand). I replaced this nu/jenu with it.