public SquareWorld(int radius)
{
this.edge = radius * 2 - 1;
var cellCount = this.edge * this.edge;
int firstX = 1 - radius;
int firstY = 1 - radius;
this.bound = IntRange.Inclusive(firstX, -firstX);
this.offset = 0 - (firstY * this.edge + firstX);
this.cells = Enumerable
.Range(0, cellCount)
.Select(_ => new SquareCell())
.ToArray();
}