My display name is my nickname at school. My friends started calling me Squirsh about two years ago, but my nickname was originally Squirshi, which is a combination of my name and the word "Squircle" which is apparantly a cross between a square and a circle.
Anyway, this is the full story about how I got my nickname:
The first time somebody called me Squirshi was when I was 11, I saw a girl weaving something that looked like a friendship bracelet except it was plastic strips instead of thread. She'd started off weaving it so that it was cylindrical and had a circular cross-section, but then about halfway through she'd changed the weaving pattern so it had a square cross-section. I was quite interested in what she was doing and, being quite oblivious to the fact that she was trying to concentrate, I started asking her "What're you doing?" over and over again until she said "I'm making a squircle, Squirshi!"
It seems she'd been trying to say my name but accidentally combined my name with the name of the thing she was making.
When I started Secondary School a few months later, one of the tasks in my English class was to go up to the front of the class and talk about an interesting or funny experience so I talked about my experience of being called Squirshi. My classmates found it hilarious and some people started calling me Squirshi. When I properly settled into school and made a few friends, they started calling me Squirshi and eventually it was shortened to Squirsh. Now I use it as my display name. 