Pull lever Combination lock [Help Needed]

[Simpanra]

Ok, i have decided to make my next video tutorial on more advanced scripting, in particular; how to make a combination to open or do something (by combo i mean like 3, 2, 4, 1, by pulling levers or books)

Lets say i have four levers, each one is called lever1, lever2, lever3 and lever4. And i want them to unlock a door, lets call the door lockeddoor1.

Please can somebody make an example script and explain it for me? =) This will be really helpful as i can then make my next video tutorial to put on my thread ^_^ all credit will go to the ones who help me =)

thank you,

Edd,