/diy/ - Do It Yourself

Ok, a few quick questions that should be fairly straight forward.
These kind of electric tea lights, what makes them flicker? There doesn't seem to be any components in them beyond the led, the battery and a very primitive switch.
Can the flickering frequency be altered somehow? As they are they are mostly on but I'd want it the other way around (I'm building some wargaming terrain and want some spooky-style flickering lamps).
Would it mess things up if I extended some wires from the led to the battery? I would like to keep the battery in a better location. (I've only worked with systems where wire gauge and length has been relatively unimportant before).