one of its legs is both the same

I've noticed for a while that I can see more of the left-hand-side of the frame when I look what feels like directly downwards but so far haven't been able to determine that it's not due to how I hold my head or left-eye-dominance PoV-override. My previous saddle (which is still mine, though it's currently being borrowed and is currently unavailable) exhibits a slight leftward lean but it's seven years old and is allowed to be a bit skewed; it also has a large rent on the right-hand side which I've never got round to taping up. This saddle has been mine for less than a year and has spent most of that time on the sparebike and was someone else's before I eBayed it, so the leftwards lean might not be all me though it's looking increasingly like that it is. I've never particularly noticed any difference in the length of my legs or the weight of my buttocks or any other bilateral asymmetries which might have caused this unless it's the way I have to lean to counteract the camera bag or the normally right-side-mounted pannier, but might try travelling with any loads centered to try and determine it it's bike-derived or due to me.