For the light-colored pieces, I used a 1" x 36" square pine(?) dowel, with a Minwax Golden Pecan stain and a basic sealer.
For the dark-colored pieces, I used a 1-1/8" x 36" round oak dowel, with a Minwax Red Mahogany stain and the same basic sealer.
I intentionally avoided varnishing or any kind of gloss finish, preferring the rougher, more natural feel of unpolished wood. Downside is that it feels just slightly too rough for my liking right now, but it's my first stab at this, so I'll solve that problem next time, and these will hopefully wear down smoother as they get used.
To make these flat on one edge, I just removed a portion wood down the long edge of the dowel before dicing it up into pieces. From there, I just sanded off all of the hard corners to give them a worn, softer feel.
The textures you're seeing are just natural from the wood itself. I didn't do anything to create them other then anything the saw might have done during cutting.
Edit: corrections to wood size and stain info.