Off to rim strips. Use the fabric strips, they offer more protection, will not rot or snap and sit better on the rim. Under the rim strip you should see spokes that run the entire length of the nipple. If your spokes do not run the full length of the nipple you are riding on hollow spokes. The third picture points to the area that will be hollow if your spoke does not insert into the nipple fully. Now imagine all your power and force from big hits being transferred into hollow nipples. Not a good way to have your wheels set up.