I started out by reflecting on the ways in which people fiddle and play with different objects. I started by observing my own behavior. I then sketched out several ideas of different designs.
With the piece of plastic, I decided to create a diamond shaped object that I could hold between my middle finger and thumb and spin around (Something I do often with my phone). I built a prototype with foam to check for the right size and shape.
I then used a dremel to cut the plastic and sanded the corners by hand till I had a smooth finish.
For the piece of wood, I toyed around with various ideas, deciding finally to make something that I could put my finger through and spin around. I experimented with various shapes, sizes and placement options for the hole. I built 3 prototypes to test my concept, and chose the design which best afforded for the interaction that I was aiming for.
I used the band saw to cut out the edges, and then drilled the hole into the piece of wood, before sanding it by hand.
I'm glad to say that everyone that I showed the piece to played with it in the exact way that I had intended without me prompting them in any way.