One of my favorite lectures from my freshman-year psychology course with Dr. Jody Esper at Valparaiso University focused on the brain's interpretation of optical illusions.

I've included one of my favorite "mind trick drawings" with my column today. It still intrigues me.

This famous perceptual illusion is sometimes called "the old/young woman illusion" or (from my 1983 psychology textbook used during 1988, my first year at VU) also referred to (politically incorrectly) as "the wife and mother-in-law" illusion.Depending on each person's focus and interpretation, the image can be seen as a beautiful young maiden with her head slightly turned OR an old crone shown in profile, complete with crooked nose.This now-famous image first became popular centuries ago, printed and passed around on an anonymous German postcard from 1888.

Depending on each person's focus and interpretation, the image can be seen as a beautiful young maiden with her head slightly turned OR an old crone shown in profile, complete with crooked nose.

This now-famous image first became popular centuries ago, printed and passed around on an anonymous German postcard from 1888.By 1890, it was so famous in Europe it was featured on posters and advertisements by the Anchor Buggy Co.For many years, U.S. historians believed the creator was British cartoonist W. E. Hill, who published it in 1915 in Puck, an American humor magazine inspired by Punch, a British magazine. However, we now know Hill adapted the figure from an original concept that was popular throughout the world on trading and puzzle cards. Still don't see both images? Here's a hint. If you only see the "ear" of the young maiden, that same "ear" is the old hag's "eye."For some, this image might inspire more of a headache than entertainment.But while visiting Pigeon Forge, Tenn., last month for my interview with Dolly Parton, published over the weekend, I stumbled on this old sketch and many others showcased at a great attraction called WonderWorks,

which is described as "an amusement park for the mind."If visiting the WonderWorks location in Pigeon Forge (I understand there are a few around the country, with even more planned), it's easy to spot it as you get into town because the entire Roman-column mansion-like museum building, including palm trees and landscaping, is upside down.Other exhibits include many child-friendly hands-on activities and opportunities for visitors of all ages to experience anti-gravity, wind tunnels, a bubble laboratory, an earthquake room and a game-intensive arcade, among numerous other fascinating finds.For more information, wonderworkstn.com or (865) 868-1800.The opinions expressed are solely those of the writer. He can be reached at philip.potempa@nwi.com or 219.852.4327.Today's Celebrity BirthdaysActor Jack Klugman is 87. Scarsdale Diet doctor murderess Jean Harris is 86. Actress Anouk Aimee and announcer Casey Kasem are 77. Actress Judy

Carne is 70. Singer Cuba Gooding of the Main Ingredient is 65. Singer Ann Peebles is 62. Singer Kate Pierson of The B-52's is 61. Singer Herbie Murrell of The Stylistics and actor Douglas Sheehan ("Knots Landing") are 60. Guitarist Ace Frehley (Kiss) and former child actor Paul O'Keefe (Ross Lane on "The Patty Duke Show") are 58. Singer Sheena Easton is 50. Actor Kevin McNally ("Pirates of the Caribbean") is 52. Director Jon Cassar ("24") is 50. Singer Sheena Easton is 49. Actor James LeGros ("Ally McBeal") is 48. Bassist Rob Squires of Big Head Todd and the Monsters is 44. Singer Mica Paris is 40. Singer-guitarist Travis Meeks of Days of the New is 30. Actress Ari Graynor ("Nick and Norah's Infinite Playlist") is 26. Singer-guitarist Patrick Stump of Fall Out Boy is 25. Actor William Moseley ("The Chronicles of Narnia") is 22.