Originally Posted by Curmudgeon
A 143 No.
An attempt to trip someone who is already prone cannot succeed; they cannot be knocked "more prone". The AoO from their attempt to stand up happens before they have risen any appreciable amount, and they are free to continue to stand up after your attack. While Knock-Down permits a trip attempt, the feat does not guarantee that success is possible.
But if the standing provoked the AoO, and it caused knock down to trigger, would you leave the turn, with the opponent back in the prone position?
: If a Large and Huge creature both have Inhuman Reach and Extended Reach, with a spiked chain (so 30ft reach for large, 35ft reach for huge) How many squares diagonal can these type of creatures threaten? (I understand the straight forward ones, those are simple just count by 5 out ward, but the diagonal ones are confusing me.
Could one simply look at magic spell lines/effects to see how lines are made?