Saw this group online and they've been working with electrically conductive carbon paint, and painting electrical circuits and drawing stiches and etching wires, it's really cool and would make a great science project at schools

 

Such paint is used to make electrolytic layers on insulating substrates. Initially, the conductivity of carbon is feeble, but as copper, nickel or other growths, the current can be increased.

If I had some my walls would be covered in circuits. I would never get my security deposit back.

I recently bought the bare conductive pen, have to say it was a bit disappointing, it was very hard to get out of the pen, too thick and gooey. I recently bought from this company, https://sites.google.com/site/thinkinkfactory123, was much happier with this product, easy to apply and the metallic silver looks really nice to the eye. I ran a few experiments and noticed a 2 ohm per square which is far better than the bare conductive gunk!

A pencil with its graphite core can leave a conductive mark, but the graphite deposit appears to be discontinuous. Thus, getting a long conductive mark may be difficult. It is easy to try and inexpensive.