'Feet' in the Bible

Someone asked me, "What do you see?" I replied, "I see a flying scroll thirty feet long and fifteen feet wide."

On that day his feet will stand on the Mount of Olives which lies to the east of Jerusalem, and the Mount of Olives will be split in half from east to west, leaving a great valley. Half the mountain will move northward and the other half southward.

But this will be the nature of the plague with which the Lord will strike all the nations that have fought against Jerusalem: Their flesh will decay while they stand on their feet, their eyes will rot away in their sockets, and their tongues will dissolve in their mouths.