Okay, so evidently there are a few Dyckia enthusiasts in the room. Here are a few pictures from my patio showing some of my favorites. The first four plants are seedlings grown from my plants. The second plant is offspring of the last plant, actually, and I suspect the difference in color is mostly due to exposure (the seedling is in 50% shade, the mother in all-day sun). They hybridize freely so there's some guessing involved.
You can tell with the bigger plants that I give them some harsh treatment (day-long sun and watering along with the succulents, when they go dry).