Knotwork is a seedling cactus with interesting, sometimes sinewy, rib shift patterns. It is likely a Malo 4 cross. If I had to guess, I would say Malo 4 x Malo 4. The mutation patterns are rib shifts, sometimes short and fast, sometimes sinewy. It appears to be very vigorous. The spine size is reasonably small. It can be very dark green, but also can be a very grey/green color from the dusty bloom that forms on the skin.