CAGradientLayer not smooth enough?
CAGradientLayer *layer = [CAGradientLayer layer];
layer.colors = [NSArray arrayWithObjects:
                (id)[[UIColor darkKinepolisColor] CGColor],
                (id)[[UIColor lightKinepolisColor] CGColor],
                (id)[[UIColor lightKinepolisColor] CGColor],
                (id)[[UIColor darkKinepolisColor] CGColor],
                nil];
layer.locations = [NSArray arrayWithObjects:
                   [NSNumber numberWithFloat:0],
                   [NSNumber numberWithFloat:0.4],
                   [NSNumber numberWithFloat:0.6],
                   [NSNumber numberWithFloat:1],
                   nil];
layer.startPoint = CGPointMake(0, 0);
layer.frame = self.layer.bounds;
layer.endPoint = CGPointMake(1, 1);
layer.contentsGravity = kCAGravityResize;
[self.layer addSublayer:layer];