The tool makes it really easy to to design characters, icons and signs, you just click on each pixel to toggle it between dark and light, and when your “character” looks right, you simply copy the code to the right and paste it into your Arduino code, and there you have your new character.
I tried to make a few different characters, as seen in the image above. If space is a little tight and you need a lot of information on screen, making special characters that combine two elements like the “degree centigrade” and “degree fahrenheit” in the image could help you out. Also signs like Ohm and micro are often useful in electronics.