The disappearance rate on falling sand entities appears to have increased. In the snapshot before last (13w39b) and versions prior with the /summon command gave you the ability to make a "fake" block by constantly spawning fallingsand every tick. Now it blinks and not only ruins the effect but gives seizures. There is no way to fix this as it seems that it somehow disappears before another tick even happens! Fails in both command minecarts and command blocks. The texture appears and disappears instantly, like I said before a new tick even happens. Also I built a redstone tick rate clock and measured the rate between the snapshots. Both balanced at 5 redstone ticks. Basically meaning the full amount of ticks I believe. Not a major issue but map makers would appreciate this feature fixed