Code in a book. Author must have been like "I'mma gonna drop this right here."

lineAtPoint.c

 -(Line *)lineAtPoint:(CGPoint)p
{
    for (Line *l in self.finishedLines){
        CGPoint start = l.begin;
        CGPoint end = l.end;

        for (float t=0.0; t<=1.0; t+= 0.05){
            float x = start.x + t * (end.x - start.x);
            float y = start.y + t * (end.y - start.y);
            
            if (hypot(x - p.x, y - p.y) < 20.0){
                return l;
            }
        }
    }
            
    return nil;
}