Hey everyone my name is Joe. I'm new to the world of lockpicking and so far I am really enjoying it. It feels very natural to me. I've been working on these two pad locks for the past week and now I am able to pick them in under 15 secs each. I'm going to pick up some more locks soon but I'm not sure what kind of locks I should look into. I'll post a picture of the two locks I've been working on for the past week, but within the second day of lock picking they just became way too easy to pick. I've done a lot of reading lately and I have quite a bit of knowledge considering I just started. I would like to pick up a bunch of locks that increase in difficulty so I continue this hobby and stay busy for a long long time. I want to work on 1 lock until I can pick it within a short amount of time every time, then move on to the next level of difficulty.
Does anybody have a simple list of locks that increase in difficulty as you go down the list?
What locks would you recommend to me for the next step? Specifically something with security pins.
These are the locks I've been messing around with

<a href="http://smg.beta.photobucket.com/user/jln2xtreme/media/image_zpsab731596.jpg.html" target="_blank"><img src="http://img.photobucket.com/albums/v332/jln2xtreme/image_zpsab731596.jpg" border="0" alt=" photo image_zpsab731596.jpg"/></a>