Forearm tattoo coverup, engineering related sleeve

This is what a business in United States was looking for in their tattoo design

Would like to cover up a stupid tattoo I got as a teenager. Would love to turn it into a sleeve of some sort. Problem is I have absolutely no idea what I want. I'm not picky, just really anything that looks good. I have a mechanical engineering background so would probably want something of that theme. I love machining, tinkering with mechanical designs, electrical circuits etc. Anything involving that would be ideal. I uploaded two pics of my arm with the tattoos I would like to get covered up with this sleeve. The money sign and MLG on the wrist, but main one I really want covered is the money sign. Average build male, 32 years old. Forearm diameter at its largest is roughly 3.9 inches. Thanks! If more info is needed please don't hesitate to contact me. Read more