Adding to what Abigail's written:
Michael Abrash covered the topic of eye-pleasing lines in detail in Zen of Graphics Programming. This book's quite fascinating, and pretty well written. And although most of the examples were (quite naturally) not in perl, all that's really needed to absorb most of the book's functionality are some basic math skills, typically algebra. You can also purchase a subscription to Byte magazine and get access to a seemingly similar book, where chapter 35 would be of particular interest.