Landolt C refers to a special type of eye chart used by eye doctors to check how well people can see. The chart has a big letter "C" on it that is rotated in different directions, like up, down, left, or right. The letters also get smaller as you move down the chart.
The doctor will ask you to cover one eye and read the "C" letter by telling them which direction it's pointing. As you go down the chart, the letters get smaller and harder to see, and the doctor will keep track of which letters you can read and which you cannot.
This test helps eye doctors determine how good your vision is and whether or not you need glasses, contacts, or other treatments to improve your eyesight. So, just like a fun game, you can show your ability to read the Letter "C" in different directions and sizes to help your doctor determine the health of your eyes!