Goal and options: how to adjust the consistency of pasta sauce
output answer: Reserved pasta water also contains starch that can be used to adjust the consistency of sauce.

Goal and options: How to groove the edges of leather.
output answer: Using a grooving tool, drag the tool in a straight line through the edges of the leather where you will be stitching.

Goal and options: To make round slices of same thickness from wood.
output answer:
Take 3-4 inch wide branches of various wood. Slice them using a band saw set at a certain depth.