I have been working on a Minetest logic unit called the Logic Gator. It is called this because at its core is a contraption that reads two bits of input and converts it so one of four mesecons is on(signaling which combination of bits it is). Two numbers in a math problem are "woven" together when input (IE to get 11101101+10011001 on a Logic Gator with an adder but no control unit, you'd have to enter 11101001111011 directly onto the logic units), which makes creating adders, subtractors, and other things that exploit the logic units easier.
I plan to create a computer and other things with the Logic Gator unit; All of my creations will be downloadable here.
4 consecutive logic gator units:
https://www.dropbox.com/s/u8vf9l0oiffqb ... r.zip?dl=1