The aliasing or whatever on the gridlines is causing that moire effect optical illusion for me and making it hard to enjoy looking for more than a few minutes.
When I get home I'll give you a dump of info. It's a 4k screen with something like 150% UI scaling. Windows. Chrome. I'll test it in Ubuntu and on my other pc.
Something to be aware of is to use integer math where possible when dealing with canvas coordinates and drawing. I found I ran into similar issues when I allowed fractions to get into my system.