Door Puzzle

[Necrosnoop110]

D&D 3.5

DM here. Any suggestions for a puzzle or game mechanic to open a door hidden in a alley way in a urban setting? Don't want it to be something to solve with a single dice roll. Would like it to be something that the whole party can be involved with.

Thanks,
Necro   

[snakeman830]

One I came up with today is a rather simple one that could probably be put anywhere.  Given it's in an urban area, there are probably people that are actually supposed to go through this door.  Give each one of these people a small snake-shaped object, including an open mouth.  The door can simply have a hint of "Infinitely open" either inscribed on it, or discovered through some other way.

Now, there is no access to the lock on the outside, so it can't be picked, but that snake object is necessary to open it.  Inserting the tail into the mouth will create an oroboros loop, which then opens the door when touched.

[ketaro]

You could make it a tile puzzle.

[Necrosnoop110]

(1) Was thinking of using one of these puzzles. Was thinking of using B.1. Snip. Any thoughts on which puzzle might work the best here?

(2) How do I handle things if they cannot solve it? Should I still allow them to access the door? 

Thanks,
Necro

[Archon]

(1) Was thinking of using one of these puzzles. Was thinking of using B.1. Snip. Any thoughts on which puzzle might work the best here?

(2) How do I handle things if they cannot solve it? Should I still allow them to access the door? 

Thanks,
Necro

You should allow them access to the door without actually achieving something; If they do not get the puzzle, but scheme another way to break in, then allow that, but if they just stand there stumped for a while and give up, you shouldn't reward that. Make them take a more second, more dangerous path, maybe?