If you draw an extra square just delete it with your eraser tool (also kept at 1 pixel width, see the red circle) it will look neater and your audience will thank you for it.
Pixel Noir is an installation for galleries: a wall inhabited by a projected living shape made of light pixels, which endlessly bounces on a black square painting hung on the wall.
黑色像素是一件室内装置作品：无数跃动的光像素点投射到挂有方形黑色画作的展厅墙上。
3
In the general ellipse - generating algorithm for raster - pixel, there are always multiplication and square root operating in the main iteration loop, so the calculating cost is more expensive.