To start the year, you might want to access some web sites that will generate interesting conversations. The drawing on the right always used to bother my students; some saw an old woman and some saw a young girl...few were able to see both. But then, many of these same students, while trying proofs, had trouble seeing the important lines in geometrical diagrams.
The following are some interesting web site options, all based on the common theme of illusions...whether data-based or visual-based.
Option 1: This one called Worldometers catches your attention by its constantly changing data. Please note the site's warning that it is not to be used as representing exact statistics....but then, given the categories involved, even approximate statistics can be alarming (or creating illusions).
Option 2: This one called Color Illusion catches your attention by its constantly moving dots. On reading the instructions, you may say "it" won't happen to you...but I have found no one who has escaped the color shift.
Option 3: If you liked that last site, this one is similar in that it contains Many Visual Illusions. It depends on more traditional static images to bother you....be prepared to spend some time playing (and scrathing your head) here.
Option 4: Now on to a final site Optical Illusions Etc that supposedly has a Sci-Fi origin. Consider the site's initial caution: "Some of the optical illusions on this blog may cause dizziness or possibly epileptic seizures. The latter happens when the brain can't handle the conflicting information from your two eyes. If you start feeling unwell when using this website, immediately cover one eye with your hand and then leave the page. Do not close your eyes because that can make the attack worse." You have been forewarned.
As a final note: My thanks to a good friend (Bob Gilda) for providing me with the links to these sites.