Armature doesn't work properly I have rigged a left foot in Blender and want to rig the other foot, but when I test the another foot, the armature didn't work well. 

The armature twitches or flickers as shown in this video.

Video Showing Issue
In the linked file there is no right leg bones so it's hard to say what's your problem. Anyway, you can easily fix it:


First give all your left leg bones a ".L" or "_L" suffix.
Then select all the left leg bones, go in the Armature menu and choose Symmetrize.
You now have right leg bones and they work.