ComboBomb by DeadEd ( http://www.deaded.com )

Choose the combinations for the lock by clicking on the numbers.  
When you have selected 4 numbers, press "Pick" to see how well you are doing.

To the right of the picked line, you are shown how well you are picking the combination lock ... "X" means there is a correct number in the correct place. 
"/" means that there is a correct number in the combination but in the wrong location.  Nothing shown means no correct numbers at all.

Have fun