radial flow lines. They are best seen near the coin's rims. The flow lines become longer, deeper, and more noticeable on coins as the die is used. I have a "dollar sized" silver British trade dollar struck at the Bombay Mint. The lines on this coin are not in the usual radial direction! They are curved away from the center. I'm trying to understand why. I was told its because the coins were struck using old screw presses sent from the Royal Mint. I'll post an image.