Rope

Rope is a refined material crafted of 3 grass; it's used in tools, logsuits, and any object or structures. It is worth 27 research points, thus making it the best way to get science(a grass gives 3, so 3 grass would give you 9).

Burning a rope will be much more efficient than logs because 1 piece of rope will last 1/2 a day.

Recipe
Wood+wood+wood=refined wood