It is a simple challenge you can do with anyone, put one line on a peace of paper, the only rules you can not change the shape of the first line, you can't erase any part of the first line. And the person doing the challenge can not draw the first line.
I did this to a coworker, I ha to take the finished drawing to the shredder before we got caught. Dirty minded people......
have fun, please feel free to link the results.

If i get enough feed back this little game may result in a free commission.