Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

What happened when the wheel was invented?

Fate has decided that you will only be pleased to meet me when you need me

Maybe that is why, when I am working, I start working

However annoying I may be to the regulars, the little ones are always inspired

I will always be waiting if you try to reach me

How many of you can guess my name, let me see

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

This is a famous paradox which has caused a great deal of argument and disbelief from many who cannot accept the correct answer. Four balls are placed in a hat. One is white, one is blue and the other two are red. The bag is shaken and someone draws two balls from the hat. He looks at the two balls and announces that at least one of them is red. What are the chances that the other ball he has drawn out is also red?

One of the leprechaun is missing if you see the two pictures attached to this question. Where did he go? When he comes back, do you know where has he been?

Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

There is something which is always coming but never arrives?