gistfile1.m

// Alien Blue - Drawing Vertical Threadlines

#define kThreadIndentSize 20.
#define kThreadLineWidth 1.

- (void) drawThreadLinesforLevel:(NSUInteger) level
{
    CGContextRef context = UIGraphicsGetCurrentContext(); 
    CGContextSetRGBFillColor(context, 0.93, 0.93, 0.93, 1.0);

    for (NSUInteger i=1; i<=level; i++)
    {
        CGRect threadLineRect = CGRectMake(kThreadIndentSize * i - (kThreadIndentSize / 2), 0, kThreadLineWidth, self.bounds.size.height);
        CGContextFillRect(context, threadLineRect);
    }
}