Half the time spent drawing this one was getting the head/helmet right. I referred to some photos of old art deco style radios and other appliances from that era, but ultimately I had to make it up, while matching the original Robocop's faceplate design.
It turned out I could have drawn it much smaller, and quicker, if I'd stuck with my 0.5mm mechanical pencil (instead of Black and Cool Grey Prismacolor Verithins), but I like to experiment. And experiments are where I very often learn what not to do.