Hey there, welcome! I definitely see an improvement between each attempt as your values are clearer and more defined. I think the main thing to focus on would be to have an equal difference from value to value, so darkening your middle grey a touch and lightening your light grey a little would create the difference in values you need. That way, the first greys are more distinguishable and clear from one another, and don't blend together. Also, try using straight lines exclusively, as this makes things both more simplified and easier to get down accurately. I hope these tips help, let me know how it goes!