"It's very simple," Alec assured him. "Each person draws a line. I suppose we should put some sort of limit on the length of the line, but I'm not sure how to do that. Anyway, each person draws a line-"
"Literal line that's straight?" Xander asked.
"Layperson's line which is allowed to be squiggly," Alec replied. "ANYWAY! Each person draws a line in any shape they desire of a reasonable length, connecting each line to the previous person's line, and we see if we can't create some kind of image without discussing anything."