Good Riddles

Question: 1 is 3, 3 is 5, 5 is 4, 4 is universal. 2 is 3, 3 is 5, 5 is 4, 4 is universal... how is this possible? (What is the rule to this sequence of numbers?)

Question: There was once three trees. The first tree did whatever the third tree did, and the third tree did what ever the second one does. What happens if tree number two gets cut down?

Question: I run over fields and woods all day. Under the bed at night I sit not alone. My tongue hangs out, up and to the rear, awaiting to be filled in the morning.

What am I?

Question: A man was able to avoid getting stuck alone on a deserted island by forgetting to put one thing on the island.What did he forget?

Question: What goes up and down the stairs without moving?