-// actually, what we want is 266.6666 for 180bpm
-// but 260 takes same amount of frames and is nicer to mappers
+// jump duration == 2*sv_jumpvelocity / sv_gravity
+// in this case: 0.65 (thus either 19 or 20 frames)
+// jump height == sv_jumpvelocity^2 / (2*sv_gravity)
+// in this case: 42.25
+// player: 24+45 qu
+// total: 111.25qu
+// this is smaller than 112 qu, so a 112 qu high corridor (7 of 8 grid units in
+// the 16 grid, and the 8th unit used for wall/floor) just lets a player jump!