Gleam, glitter, glow,

They're moving very slow,

Sometimes on a smooth surface,

Often searching they\'re way down,

Between hunderds of obstacles,

They can be seen in every town,

Always moving and searching their way,

Again and again, everyday,

They merge and seperate with their species all the time,

And they can also be found, in this little rhyme.

A woman lived in an apartment building on the seventh floor. Every morning she took the lift to the ground floor and went to her work. But when she came home, she took the lift to the fourth floor and then continued by walking the stairs up. Why would she do that?

You can be the last joining person, but you will never be first. What is it?